Method and apparatus for forming a paper or tissue web

ABSTRACT

A method and apparatus for transferring a vibrational force to the wire of a papermaking machine in order to re-align the fibers of the web forming on the wire or to clean press section felts. In some embodiments, the apparatus is a vibrational device including at least one vibration-inducing mechanism, a vibrational head coupled to the vibration-inducing mechanism for vibrating the wire, and a dampening mechanism coupled between the vibrational head and the vibration-inducing mechanism.

CROSS-REFERENCE TO RELATED APPLICATION

Priority is hereby claimed to U.S. patent application Ser. No.10/646,367, filed Aug. 22, 2003, and to U.S. patent application Ser. No.10/027,507 filed on Dec. 21, 2001, the entire disclosure of which areincorporated herein by reference.

FIELD OF THE INVENTION

This invention relates generally to forming a paper or tissue web, andmore particularly to apparatuses and methods for improving the fiberdistribution within a paper or tissue web.

BACKGROUND OF THE INVENTION

Paper and tissue are typically manufactured in a continuous sheet on apapermaking machine. One of the most common papermaking machines is theFourdrinier machine. Fourdrinier machines generally include at leastthree sections: a wet-end section, a press section, and a dryer section.The wet-end section, which can be 40 to 100 feet in length, is alsoreferred to as the forming section or the Fourdrinier table. In thewet-end section, stock flow is transferred from a headbox onto a moving,endless belt of wire-mesh screen, referred to as the Fourdrinier wire,or simply as the “wire.” Stock flow is normally a combination of woodfibers, fines and fillers, chemical additives such as bonding agents,and water. Wood fibers typically range in length from 400 to 7,000microns and in width from 20 to 100 microns, depending on the species ofthe wood. Stock flow typically has a liquid consistency of 99 percentand a fiber consistency of approximately 0.2 to 1 percent (althoughother fiber consistencies are possible), depending on the grade andweight of the paper or tissue being manufactured.

The function of the headbox is to distribute stock flow with a uniformfiber distribution to the wire in order to produce a sheet of paperhaving uniform properties across the width of the wire (cross-machinedirection), along the length of the wire (machine direction), andthrough the cross-section of the sheet of paper (Z direction). Theheadbox distributes stock flow to the wire at an angle other thanabsolute tangent, referred to as the angle of impingement. If the angleof impingement is steep, i.e., close to absolute tangent, thearrangement of the headbox is referred to as pressure forming. If theangle of impingement is shallow, i.e., not close to absolute tangent,the arrangement of the headbox is referred to as velocity forming.

The wire runs over a breast roll, which is usually located under theheadbox. The wire is typically not a permanent part of the papermakingmachine and requires periodic replacement. One condition leading topremature failure of the wire is the plugging of the openings in theporous wire by the fibers, fines, and fillers of the web beingtransported by the wire. Normally, the wire is a delicate, finely wovenmetal or synthetic fiber cloth that allows for drainage of the water,but retains most of the fibers. The strands of the wire are commonlymade of finely drawn and woven, annealed bronze or brass.

After the stock flow is delivered from the headbox to the wire in thewet-end section of a Fourdrinier machine, the fibers are initially heldin free suspension within the water as relatively mobile individualfibers or as part of a network, referred to as a floc. The fibers andflocs in the stock flow begin to form a wet sheet of matted pulp,referred to as an embryonic web. While not subscribing to any particularmanner in which the embryonic web is formed, normally either bondingagents in the stock flow cause an electro-chemical bond or the bond isproduced through physical entanglement. The embryonic web forms as thefibers and flocs in free suspension begin to settle in layers on thewire. Ideally, the fiber distribution within the web would be consistentin the cross-machine direction, the machine direction, and the Zdirection. However, due to gravitational forces, the bottom-most layersof fibers that settle directly on the wire are typically more dense thanthe upper-most layers of fibers. The web normally has boundary layers(i.e., the two external layers of the web, such as the bottom-most layerof fibers that settles directly on the wire and the upper-most layer offibers) and internal web fibers (fibers in the layers of the web betweenthe two external layers of fibers). The web may consist of approximately2 to 100 layers of fibers.

In order to assist in the formation of the embryonic web, as the wiremoves away from the headbox, various suction devices can be used todrain water from the stock flow. The suction devices in the Fourdriniermachine typically include a series of stationary blades or foils. Thestationary foils remove water from the stock flow by creating a vacuumon the downstream side of the blade where the wire leaves the bladesurface. As the wire moves across a series of stationary foils, thedownstream side of each stationary foil creates a vacuum that pullswater from the stock flow, while the upstream side of each stationaryfoil pulls the water off of the wire. Some of the wood fibers, fines,and fillers are pulled off of the wire along with the water being pulledoff of the wire. The amount of fibers, fines, and fillers that areretained on the wire while the water is being pulled off of the wire isreferred to as retention.

Once the wire passes over the stationary foils, the wire normally passesover a drive roll or couch roll, over a series of return rolls, and backto the breast roll. At the end of the wet-end section of the Fourdriniermachine, the web can have a water consistency of approximately 80percent and a fiber consistency of approximately 20 percent. At thispoint, the web can normally support its own weight. Other water andfiber consistencies are also possible at this point for enabling the webto support its own weight.

Next, the web can be transferred from the wet-end section of theFourdrinier machine to the press section at the couch roll. The wet webof paper is normally transferred from the wire of the wet-end section toa screen. The screen can be a woolen felt screen, referred to as a felt,acting as a conveyor belt to carry the web through the press section.The felt is typically porous media that provides space and channels forwater removal. The felt can also act as a textured cushion or shockabsorber for pressing the moist web without crushing the web. Thetexture and character of the felt varies according to the grade of thepaper being made. The felt normally carries the web through two or morepress rolls, which mechanically squeeze water from the web. A variety ofsuction devices, one of which is commonly referred to as a uhle box, canalso be used to remove water from the felt. The press rolls oftenconsist of a steel or cast iron core covered by a bronze or stainlesssteel inner shell and an outer rubber shell. At the end of the presssection of the Fourdrinier machine, the web typically has a consistencyof approximately 40 percent water and 60 percent fiber, although otherweb consistencies at this stage are possible.

After the press section, the web can be transferred to fabric dryerfelts that carry the web through the dryer section. The dryer felts aremost commonly constructed of a highly permeable cotton blend oropen-mesh fabric. The web is normally held firmly against a number ofsteam-heated cylinders or drums by the dryer felts in order to evaporatethe remaining water. As the web passes from one cylinder to another,first the felt side and then the web side are pressed against the heatedsurfaces of the cylinders. In addition, hot air may be blown onto theweb and between the cylinders to vaporize water from the web. At the endof the dryer section, the completed web typically has a consistency ofapproximately 1 to 10 percent water and approximately 90 to 99 percentfiber, although other web consistencies are possible at this stage.

The quality of the paper web produced in the papermaking process dependsin part on the orientation of the fibers and the consistency of fiberdistribution when the embryonic web is formed in the wet-end section ofthe Fourdrinier machine. The orientation of the fibers within theembryonic web first depends on the distribution of the stock flow to thewire by the headbox. In a pressure forming arrangement of the headbox,the web's boundary layer fibers often become impregnated in the wire.When the web is later transferred from the wire, the boundary layerfibers impregnated in the wire are pulled from the web, leaving smallholes in the web. These small holes in the web result in a web that isnot as smooth on one side as it is on the other (often called the“phenomena of two-sidedness”). Also, in a pressure forming arrangement,the web's internal layer fibers become forcibly and sporadicallymisaligned. In a velocity forming arrangement of the headbox, the sheetis formed through a thickening mechanism. This thickening mechanism isdue in part to gravitational forces pulling the fibers and the waterdown through the wire, which causes the bottom-most layers of fibersthat settle directly on the wire to be more dense than the upper-mostlayers of fibers. This high-density layer prevents fibers, fines, andfillers from being pulled through the wire (i.e., higher retention).This high-density layer also prevents water from draining through thewire, resulting in two-sidedness. Both the phenomena of two-sidednessand the disparate orientation of internal layer fibers reduce thequality of the finished paper web.

As water is mechanically squeezed from the paper web in the presssection, fines, fillers, and fibers become impregnated in the feltcarrying the paper web. The fines, fillers, and fibers plug the felt'swater removal channels, resulting in the felt becoming less efficient inremoving water from the paper web. As the felt in the press sectionbecomes less efficient in removing water from the web, the dryer sectionmust carry the burden of removing more water from the paper web.

A long-standing problem with papermaking machinery and processes is thelarge amount of energy required to run the machinery and to producepaper in such processes. A significant portion of this energy isconsumed within the dryer section of the papermaking machine. Paper webshaving poor fiber formation require significantly more heat to dry thanpaper webs with good fiber formation and distribution. Therefore, theproblems described above regarding fiber misalignment and poor fiberdistribution result in paper that requires more energy to dry and thatis more costly to produce.

In addition, paper having poor fiber formation is typically lower inmachine direction tensile strength when compared with the same grade ofpaper with a more consistent fiber distribution. This may requireexpensive chemical additives to increase web strength and can requiremore sizing, coating, calendaring, and converting operations to producean acceptable paper product. Improving fiber formation by using morehighly refined stock fibers can help to address these issues, but at asignificantly increased pulp cost.

In light of the problems and limitations described above, a need existsfor a method and apparatus for increasing the quality and manufacturingefficiency of a finished paper web by reducing the phenomena oftwo-sidedness, improving the distribution of internal layer fibers inthe web, lowering the cost of web production through reduced energyrequirements, reducing the amount of chemical additives needed foracceptable web strengths, enabling the use of less refined or lowerquality stock, improving the retention of fines and fillers within theweb, and keeping the forming and press fabrics clean. Each embodiment ofthe present invention achieves one or more of these results.

SUMMARY OF THE INVENTION

Preferred embodiments of the present invention provide a papermakingmethod and apparatus to improve the quality of a paper web by reducingthe phenomena of two-sidedness, by improving the alignment anddistribution of the fibers in the web, and by reducing the energyrequirements of the papermaking process by increasing water removal fromthe web in the wet-end and press sections of the paper making machine.As used herein and in the appended claims, reference to a paper web isintended to refer to any type of paper or tissue web produced with apapermaking machine.

In some embodiments of the present invention, stock flow, includingfibers and water, is discharged from a headbox onto a wire. Avibrational force is transferred to the wire in order to re-align thefibers. In addition, the water from the stock flow is drained to causethe fibers to form a web. The energy imparted to the wire by thevibrational force preferably causes the boundary layer fibersimpregnated in the wire to be released from the wire. The energyimparted to the wire by the vibrational force also preferably causesrelease of internal layer fibers that have begun to form the embryonicweb. The internal layer fibers can then re-align and re-settle on thetraveling wire in a more natural and uniform pattern. As the internallayer fibers re-settle, the fibers can penetrate into empty voids withinthe web. Preferably, the vibrational force is transferred to the wire ofthe papermaking machine before significant water removal takes place,i.e. during the formation of the embryonic web. In some highly preferredembodiments of the present invention, the vibrational force istransferred to the underside of a substantially horizontal wire, such asthe wire of a Fourdrinier papermaking machine. In these and otherembodiments, a vibrational force is transferred to the forming or pressfabrics of the papermaking machine in order to release the fibers,fines, and fillers that have become impregnated in the forming or pressfabrics. In such embodiments, the vibrational force can be used inconjunction with conventional suction devices, if desired, in order tomaintain the cleanliness and water removal efficiency of the fabrics.

Some preferred embodiments of the present invention employ a papermakingmachine vibrational device having a vibrational device frame, at leastone vibration-inducing mechanism coupled to the vibrational deviceframe, and a vibrational head coupled to the vibration-inducingmechanism. Any number of such vibrational devices can be locatedadjacent to the web-forming wire, adjacent to the press felt, oradjacent to both the web-forming wire and the press felts for impartingvibration to the wire or press felt as described above. The vibrationalhead of the vibrational device preferably engages the wire or press feltof the papermaking machine to impart a vibrational force to the wire orpress felt. In some embodiments, the vibrational device is positionedunder the wire or press felt in an orientation perpendicular to thedirection of travel of the wire or press felt. The vibrational devicecan span the entire width or substantially the entire width of the wireor press felt in order to impart the vibrational force to the entirewidth of the web.

In some embodiments of the present invention, the vibrational deviceframe is mounted to the papermaking machine frame. The vibrationaldevice frame can have a truss network mountable to the papermakingmachine frame and supporting the vibration-inducing mechanisms and thevibrational head under the wire or press felt. In some preferredembodiments, the vibrational device includes a vertical adjustmentmechanism coupled to the truss network to allow for vertical adjustmentof the vibrational device with respect to the wire or press felt.

The vibration-inducing mechanisms are preferably pneumatic, hydraulic,or electric mechanisms that transfer a vibrational force to thevibrational head and wire or press felt. Although any type of vibrationcan be transferred to the head (and wire or press felt) in this manner,the vibration is preferably high frequency and low amplitude.Preferably, the frequency and amplitude of the force transferred by thevibration-inducing mechanisms can be varied through the use of asolenoid valve or an amplifier, if desired. In some embodiments, thefrequency and amplitude of the force transferred by eachvibration-inducing mechanism can be varied independently, in order toimpart different forces to different portions of the web. For example,the frequency and amplitude of the forces transferred by two or morevibrational devices spaced in the cross-machine direction can vary togenerate different vibration frequencies and amplitudes across the wireor press felt in the cross-machine direction. Preferably, a slidingmechanism is used to couple the vibration-inducing mechanisms to thevibrational head, thereby enabling quick and easy vibrational headreplacement (even during operation of the papermaking machine in someembodiments).

The vibrational head preferably includes a land area through which thevibrational force is transferred from the vibrational head to the wireor press felt. In some embodiments of the present invention, the landarea includes an upstream portion which slopes vertically downward fromthe wire or press felt at a lead angle, so that the lead angle pusheswater up into the wire or press felt when the vibrational head engagesthe underside of the wire or press felt. The land area can also includea downstream portion which slopes vertically downward from the wire orpress felt at a relief angle, so that the relief angle induces a vacuumwhen the vibrational head engages the underside of the wire or pressfelt. In other embodiments of the present invention, the land area has aconcave configuration.

In some highly preferred embodiments of the present invention, alubrication shower is positioned within the wet-end section or withinthe press section of the Fourdrinier machine upstream from thevibrational device in order to lubricate the wire or press felt, inorder to re-fluidize the fibers within the web before the fibers reachthe vibrational device, and in order to minimize air entrapment in thenip (i.e., vacuum) formed between the traveling wire or press felt andthe vibrating head.

The vibrational device according to some embodiments can include one ormore dampening mechanisms coupled between, adjacent to, or in anysuitable position with respect to the vibration-inducing mechanisms andthe vibrational head. In some embodiments, the vibrational device caninclude two or more vibration-inducing mechanisms and a vibrational headincluding a single vibrational element and two or more support members.A vibration-inducing mechanism can be coupled to each one of the supportmembers. In addition, a dampening mechanism can be coupled between thetwo or more support members and the single vibrational element.

Further objects and advantages of the present invention, together withthe organization and manner of operation thereof, will become apparentfrom the following detailed description of the invention when taken inconjunction with the accompanying drawings, wherein like elements havelike numerals throughout the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention is further described with reference to theaccompanying drawings, which show a preferred embodiment of the presentinvention. However, it should be noted that the invention as disclosedin the accompanying drawings is illustrated by way of example only. Thevarious elements and combinations of elements described below andillustrated in the drawings can be arranged and organized differently toresult in embodiments which are still within the spirit and scope of thepresent invention.

In the drawings, wherein like reference numerals indicate like parts:

FIG. 1 is a perspective view of a papermaking machine wet-end sectionhaving vibrational devices according to a preferred embodiment of thepresent invention;

FIG. 2 is side elevational view of the papermaking machine shown in FIG.1;

FIG. 3 is a perspective view of a wire portion of the papermakingmachine shown in FIG. 1;

FIG. 4 is a detail view of the papermaking machine shown in FIG. 1;

FIG. 5 a is a front elevational view of a vibrational device used in thepapermaking machine shown in FIG. 1, viewed from line 5-5 of FIG. 4;

FIG. 5 b is a front elevational view of an alternative vibrationaldevice according to the present invention, viewed from line 5-5 of FIG.4;

FIG. 5 c is a detail view of the vibrational device shown in FIG. 5 a,used with the truss of FIG. 5 b;

FIG. 5 d is a detail side view of an alternative vibrational deviceaccording to the present invention;

FIG. 6 a is a side elevational view of the vertical adjustment mechanismof the vibrational device illustrated in FIG. 5 a, viewed from line 6a-6 a of FIG. 5 a;

FIG. 6 b is a side elevational view of the vertical adjustment mechanismof the vibrational device illustrated in FIG. 5 c, viewed from line 6b-6 b of FIG. 5 c;

FIG. 6 c is a side elevational view of a vertical adjustment andisolation mechanism according to another embodiment of the presentinvention;

FIG. 7 a is a cross-sectional view of the vibrational device shown inFIG. 5 a, taken along line 7 a-7 a of FIG. 5 a;

FIG. 7 b is a cross-sectional view of the vibrational device shown inFIG. 5 b, taken along line 7 b-7 b of FIG. 5 b;

FIG. 7 c is a cross-sectional view of the vibrational device shown inFIG. 5 c, taken along line 7 c-7 c of FIG. 5 b;

FIGS. 8 a-8 e are cross-sectional views of different embodiments ofvibrational heads for a vibrational device according to the presentinvention;

FIG. 9 a is a schematic representation of stock flow settling on a wirewithout a vibrational force;

FIG. 9 b is a schematic representation of stock flow settling on a wirewith a vibrational force;

FIG. 10 is a graph of the sheet properties of a paper sheet in thecross-machine direction (width) of the paper sheet;

FIG. 11 is a schematic illustration of a papermaking machine having awet-end section, a press section, and a dryer section;

FIG. 12 is a side elevational view of a vibrational device according toan embodiment of the present invention, positioned within the presssection of a papermaking machine;

FIG. 13 is a schematic representation of a felt for use in the presssection of a papermaking machine;

FIGS. 14 a and 14 b are cross-sectional views of a vibrational devicehaving dampening mechanisms according to another embodiment of thepresent invention;

FIG. 15 is a front elevational view of a vibrational device having asingle vibrational element mounted to multiple support members accordingto another embodiment of the present invention; and

FIG. 16 is an exploded perspective view of the vibrational device ofFIGS. 14 a and 14 b.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

With reference to FIGS. 1 and 2, a preferred embodiment of the presentinvention employs a papermaking machine wet-end section 10 and avibrational device 100. The papermaking machine wet-end section 10 canprecede the press and dryer sections in a conventional papermakingmachine. The papermaking machine wet-end section 10 as shown in FIG. 1is also referred to as the forming section or the Fourdrinier table ofthe papermaking machine. The papermaking machine wet-end section 10preferably includes a papermaking machine frame 12, a headbox 14, a wire16, a breast roll 22, a couch roll 24, a plurality of return rolls 26,and a plurality of suction devices 28.

The headbox 14 is positioned adjacent to the papermaking machine frame12 in order to distribute stock flow onto the wire 16. Any conventionalheadbox in the papermaking art can be employed in order to distributestock flow onto the wire 16. The headbox 14 preferably distributes stockflow to the wire 16 in order to produce a web having uniform propertiesacross the width of the wire 16, referred to as the cross-machinedirection (CD), along the length of the wire 16, referred to as themachine direction (MD), and through the cross-section of the web,referred to as the Z direction (Z), as shown in FIG. 1. As best shown inFIG. 4, the headbox 14 preferably distributes stock flow to the wire 16at an angle of impingement α, which is an angle other than absolutetangent to the wire 16. The angle of impingement α is the angle betweentwo portions of the headbox 14, namely an apron lip 15 and a slice lip17. If the angle of impingement α is steep, i.e., close to absolutetangent to the wire 16, the arrangement of the headbox is referred to aspressure forming. If the angle of impingement α is shallow, i.e., notclose to absolute tangent, the arrangement of the headbox 14 is referredto as velocity forming.

The wire 16, which may also be referred to as the Fourdrinier wire, ispreferably a moving, endless belt of wire-mesh screen. The wire 16 ismovably coupled to the papermaking machine frame 12 via several rolls ina manner that provides an endless conveyor belt for receiving andtransporting stock flow distributed by the headbox 14. The wire 16 firstwraps around the breast roll 22, (which is preferably positionedadjacent to the headbox 14 and generally directly under the headbox 14),stretches from the breast roll 22 across the length of the wet-endsection 10 to the couch roll 24, wraps around the couch roll 24, andstretches around the plurality of return rolls 26 to return to thebreast roll 22. One having ordinary skill in the art will appreciatethat the wire 16 can be driven about other elements in anendless-conveyor arrangement, such as by being passed around one or moresprockets, pulleys, or other preferably rotatable elements.

As shown in FIG. 3, the wire 16 is preferably a delicate, finely wovenmetal or synthetic fiber cloth that allows the drainage of water, butretains most of the fibers from the stock flow. Although finely wovenmetal or synthetic fiber wire is preferred, any other type ofpapermaking wire can be employed in connection with the presentinvention. In one highly preferred type of wire shown in FIG. 3, aplurality of main strands 18 and a plurality of connecting strands 20are woven together to form the wire 16. The plurality of main strands 18and the plurality of connecting strands 20 can be made of finely drawnand woven, annealed bronze or brass, or can be made of otherconventional wire materials as desired. For example, the plurality ofmain strands 18 and the plurality of connecting strands 20 can insteadbe made of polyester monofilaments. The weave of the wire 16 can bevaried in order to inhibit or aid drainage through the wire 16. One ofordinary skill in the art will appreciate that the weave pattern of thewire 16 can be of single, double, triple, or any other layer design andtherefore needs no further description herein. The wire 16 is preferablynot a permanent part of the papermaking machine wet-end section 10 andcan be replaced in a conventional manner.

As shown in FIGS. 1 and 2, a plurality of devices 28 are preferablyemployed to control water within and exiting from the stock flow,leaving a wet sheet of matted pulp, i.e. the web, that travels on thewire 16. In the highly preferred embodiment shown in FIGS. 1 and 2,these devices 28 include an initial forming board 30, a plurality offoil boxes 32, and at least one vibrational device 100. The initialforming board 30 is preferably an elongated board having a flat topsidepositioned under the wire 16. Alternative types of initial formingboards can instead be used as desired. Preferably, the initial formingboard 30 is positioned downstream from the headbox 14 so that it is thefirst of the devices 28 to engage the wire 16. In this position, theinitial forming board 30 creates an initial dwell time during which asmall amount of water is drained from the stock flow and the web isallowed to begin forming as the wire 16 travels over the initial formingboard 30. The initial forming board 30, and forming boards in general,are well-known devices in the papermaking art and are not thereforedescribed further herein.

The plurality of foil boxes 32 are preferably positioned under the wire16, downstream from the initial forming board 30, and run in thecross-machine direction. Preferably, each one of the plurality of foilboxes 32 is coupled to the papermaking machine frame 12 and includes aplurality of T-bars 34 and a plurality of stationary (or adjustable)foils or blades 36 coupled to the plurality of T-bars 34. As isconventional in the papermaking industry, the stationary foils 36 areeach preferably 2½ inches wide. However, the stationary foils 36 may beany width. The stationary foils 36 each preferably have a lead anglethat strips water off of the wire and a surface downstream from the leadangle that creates a vacuum to pull water down from the wire 16. Thesurface downstream from the lead angle is preferably flat, but can beshaped in a number of different manners to generate vacuum downstream ofthe lead angle (including without surfaces that are wave-shaped,stepped, multi-faceted, curved convexly and/or concavely, and the like).The lead angle of each subsequent, downstream stationary foil 36 stripsthe water off of the wire 16 that was pulled down by the vacuum createdby the preferably flat surface of the preceding, upstream stationaryfoil 36. In this manner, water is drained from the wire 16 in thewet-end section 10 and the web begins to form. The wet-end section 10can include a large number (e.g., 100) of stationary foils 36 coupled tothe plurality of foil boxes 32. It should be noted that stationary foils36 need not necessarily be connected to or otherwise be used inconjunction with foil boxes 32, although foil boxes 32 are a preferredmanner of collecting and transporting water from beneath the wire 16. Inaddition, although T-shaped bars 34 are a highly preferred manner ofconnecting the stationary foils 36 to associated framework of thepapermaking machine, the stationary foils 36 can be connected in desiredlocations in any other conventional manner, such as by fastening thestationary foils 34 with one or more bolts, screws, clamps, rivets,pins, or other conventional fasteners, by snap-fitting the foils toconnecting points on the papermaking machine, and the like. Stationaryfoils, their manner of operation and connection, and the various formsof stationary foils are also well-known suction devices in thepapermaking art and are not therefore described further herein.

The papermaking machine wet-end section 10 preferably also includes atleast one vibrational device 100. As shown in FIGS. 5 a and 5 b, thevibrational device 100 includes a vibrational device frame 102 mountableto the papermaking machine frame 12 (or to other positions inside oradjacent to the papermaking machine frame 12), one or morevibration-inducing mechanisms 104 coupled to the vibrational deviceframe 102, a vibrational head 106 coupled to the vibration-inducingmechanisms 104, and one or more vibration isolators 105 coupled betweenthe vibrational head 106 and the vibrational device frame 102. Thevibrational device frame 102 preferably includes a truss network 108which provides a bridge between each side of the papermaking machineframe 12 for supporting the vibrational device 100 under the wire 16.The truss network 108 includes a horizontal truss 110, a pair ofdiagonal trusses 112 a and 112 b coupled to each end of the horizontaltruss 110, and a pair of brackets 114 a and 114 b coupled to the ends ofthe diagonal trusses 112 a and 112 b. Preferably, the horizontal truss110 is mounted under the wire 16 and runs in substantially thecross-machine direction. Preferably, the horizontal truss 110 spans theentire width of the wire 16.

The diagonal truss 112 a is coupled between a first end 116 a of thehorizontal truss 110 and the bracket 114 a. The diagonal truss 112 b iscoupled between a second end 116 b of the horizontal truss 110 and thebracket 114 b. Rather than using a single horizontal truss to supportthe vibrational device 100, the pair of diagonal trusses 112 a and 112 bare preferably used to position the horizontal truss 110 somewhat belowthe height of the papermaking machine frame 12. However, a singlehorizontal truss could be used to support the vibrational device 100.

In other preferred embodiments as shown in FIGS. 5 b and 5 c, avibrational device 200 includes a truss network 208. The truss network208 includes a first horizontal truss 210, a vertical truss 212, asecond horizontal truss 214, and a diagonal support truss 216. The firsthorizontal truss 210 is coupled to a first end 218 of the vertical truss212, and the second horizontal truss 214 is coupled to a second end 220of the vertical truss 212. The diagonal support truss 216 is coupledbetween the second horizontal truss 214 and the vertical truss 212. Theembodiment of the present invention in FIG. 5 c is an example of how thetrusses, truss ends, and vertical adjustment mechanisms (described ingreater detail below) of the various embodiments of the presentinvention can be interchanged as desired.

Still other truss network shapes and designs are possible for servingthe purpose of supporting the vibrational devices 100, 200 adjacent tothe wire 16, each one of which falls within the spirit and scope of thepresent invention. Specifically, any truss element or structure havingany shape and being made from any number of elements (including withoutlimitation plates, beams, rods, bars, and the like) connected togetherin any conventional manner could be used to support the vibrationaldevice 100, 200 from beneath as shown in the figures or from any otherlocation on the vibrational device 100, 200. The resulting truss elementor structure can have any shape desired, and can be connected to thepapermaking machine frame in any conventional manner (i.e., with orwithout brackets). Most preferably however, the truss element orstructure provides substantially no vertical deflection in the center ofthe cross-machine direction of the wire 16. Put differently, the trussnetwork preferably provides a mounting base for the vibrational device100, 200 that runs in the cross-machine direction and is completelystationary with respect to the vertical orientation of the wire 16.

Although the vibrational device 100, 200 is preferably connected to andsupported by the horizontal truss 110, 210 as described above, it shouldbe noted that in some alternative embodiments the vibrational device100, 200 is connected directly to a member of the papermaking machineframe (e.g., a beam, plate, stretcher, or other element runningpartially or fully across the papermaking machine in the cross-machinedirection). This papermaking machine frame member can be rigidly andpermanently attached to the remainder of the papermaking machine or canbe adjustable as described in more detail below with regard to thehorizontal truss 110, 210 in the illustrated preferred embodiments.

With particular reference to FIG. 6 a, each bracket 114 a, 114 b in theillustrated preferred embodiment of FIGS. 4 and 5 a preferably has abottom plate 117 and a top plate 118 coupled between a verticaladjustment mechanism 120. As shown in FIG. 5 a, the bottom plate 117preferably includes a horizontal engagement surface 122 and a pair ofdiagonal engagement surfaces 124 a and 124 b. The diagonal engagementsurfaces 124 a and 124 b are preferably configured to form a narrowbottom opening that slopes to meet the horizontal engagement surface 122to form a broader top opening, i.e., a female dovetail configuration.The female dovetail configuration of the bottom plate 116 is connectableto a dovetail support member 126 having a male dovetail configurationcoupled to the papermaking machine frame 12. As best shown in FIG. 1,the dovetail support member 126 extends along at least a portion (andmore preferably, a substantial portion) of the length of the papermakingmachine wet-end section 10 parallel to the machine direction of the wire16. Preferably, the dovetail support member 126 permits additionaldevices 28 to be mounted to the papermaking machine frame 12 and/orpermits adjustment of the position of the devices 28 along thepapermaking machine frame 12.

As shown in FIG. 6 a, the top plate 118 of each of the brackets 114 aand 114 b is preferably a horizontal plate coupled to the bottom plate117 via the vertical adjustment mechanism 120. The vertical adjustmentmechanism 120 preferably includes a threaded rod 128 a and a threadedaperture 128 b on each end of the truss 110. As shown in FIG. 5, thebrackets 114 a and 114 b are each coupled to the truss 110 by thethreaded rod 128 a passed through at least part of the bracket 114 a,114 b and through the threaded aperture 128 b in the truss 110. A nut130 on each of the threaded rods 128 a can be turned to change theheight of the truss 110 in the brackets 114 a, 114 b. The threaded rod128 a can also include a mechanical stop (such as a collar, pin, oranother nut secured in a desired position on the threaded rod 128 a, notshown) to prevent the vertical adjustment mechanism 120 from being usedto raise the vibrational device 100 above a pre-determined verticalorientation with respect to the wire 16. Most preferably, the mechanicalstop prevents the vibrational device 100 from being raised to a positionin which the vibrational device 100 will damage or break through thewire 16. Preferably, the vertical adjustment mechanism 120 is used tohelp provide proper contact between the vibrational device 100 and thewire 16. If desired, the vertical adjustment mechanism 120 in each ofthe brackets 114 a and 114 b can be adjusted independently in order toadjust for any differences in the vertical height of each side of thepapermaking machine frame 12 with respect to the wire 16.

A dovetail connection between a bracket 114 a, 114 b and the papermakingmachine frame (or the floor) is a highly preferred manner in which toconnect the horizontal truss 110 to the papermaking machine frame (orthe floor). One having ordinary skill in the art will appreciate that anumber of other manners exist for establishing this connection, somepermitting adjustment of the connection location as mentioned above, andothers not permitting such adjustment. By way of example only, eachbracket 114 a, 114 b can be attached to the papermaking machine frame orfloor by bolts, rivets, pins, screws, nails, or other conventionalfasteners, by welding or brazing, by one or more clips or clamps, andthe like. Some of the manners of connection permit adjustment of theposition of the brackets 114 a, 114 b, such as bolts or pins releasablyreceived within different apertures along the papermaking machine frame,clips or clamps holding the brackets 114 a, 114 b to a rail, lip, bar,flange, or other portion of the papermaking machine frame, and the like.In some embodiments, the brackets 114 a, 114 b can be retained indifferent positions along the papermaking machine frame by the weightupon the brackets 114 a, 114 b. Detents, recesses, notches, or otherfeatures of the papermaking machine frame can assist in retaining thebrackets 114 a, 114 b in desired positions in such cases.

FIG. 6 b is a side elevational view of the vibrational device 200illustrated in FIG. 5 b. As shown in FIG. 6 b, the second horizontaltruss 214 is coupled to a vertical adjustment mechanism 222. Thevertical adjustment mechanism 222 includes a threaded rod 224 a passedthrough a threaded aperture 224 b in the second horizontal truss 214.The threaded rod 224 a is preferably coupled to a bottom plate 217 inorder to couple the vertical adjustment mechanism 222 to the dovetailsupport member 126 of the papermaking machine frame 12. The secondhorizontal truss 214 is secured to the threaded rod 224 a by a top nut226 and a bottom nut 228. The threaded rod 224 a can also include anadjustment nut 230 that can be turned to change the height of the secondhorizontal truss 214 with respect to the papermaking machine frame 12.If desired, one or more supports 232 a and 232 b can be coupled to thesecond horizontal truss 214 to prevent the second horizontal truss 214from being adjusted below a predetermined level.

FIG. 6 c is a side elevational view of another vertical adjustment andisolation mechanism 1120 which is an alternative embodiment of thevertical adjustment mechanisms 120 and 222 shown and described abovewith respect to FIGS. 6 a and 6 b. With the exception of mutuallyinconsistent elements and features between the embodiments of FIGS. 6 aand 6 b and the embodiment of FIG. 6 c, reference is made to thedescription above regarding the vertical adjustment mechanisms 120, 222described earlier for a more complete understanding of the elements,features, and alternatives of the mechanism 1120 illustrated in FIG. 17.Also, elements and features of the vertical adjustment and isolationmechanism 1120 illustrated in FIG. 17 having a form, structure, orfunction similar to that found in the vertical adjustment mechanisms 120and 222 shown and described with respect to FIGS. 6 a and 6 b are givencorresponding reference numbers in the 1000 series.

Referring to FIG. 6 c, a dovetail support member 1126 can be coupled toa papermaking machine frame (not shown). The vertical adjustment andisolation mechanism 1120 can be coupled to the dovetail support member1126 and a horizontal truss 1214 of any type described herein. In someembodiments, the vertical adjustment and isolation mechanism 1120includes two threaded rods 1224 a passing through two threaded apertures1224 b in the horizontal truss 1214. The threaded rods 1224 a can becoupled to a bottom plate 1217 in order to couple the verticaladjustment and isolation mechanism 1120 to the dovetail support member1126 of the papermaking machine frame. The horizontal truss 1214 can besecured to the threaded rods 1224 a by nuts 1228. The threaded rods 1224a can also include adjustment nuts 1230 that can be turned to change theminimum height of the horizontal truss 1214 with respect to thepapermaking machine frame. If desired, one or more supports 1232 a and1232 b can also be coupled to the horizontal truss 1214 to prevent thehorizontal truss 1214 from being adjusted below a predetermined level.

As shown in FIG. 17, the vertical adjustment and isolation mechanism1120 also includes a vibrational isolator 1250. The vibrational isolator1250 can at least partially isolate the papermaking machine frame fromvibrations of any one of the vibrational devices 100, 200, 1000, andlikewise, to at least partially isolate any one of the vibrationaldevices 100, 200, 1000 from vibrations of the papermaking machine frame.In some embodiments, the vibrational isolator 1250 includes one or moregas or fluid-filled bags or other gas or fluid-filled deformableelements positioned between the horizontal truss 1214 and the bottomplate 1217 and/or the dovetail support member 1126. In otherembodiments, the vibrational isolator 1250 can be a pad, block, or otherelement made from a resilient compressible and vibration-dampingmaterial such as rubber, plastic, urethane, wool, cork, and the likepositioned between the horizontal truss 1214 and the bottom plate 1217and/or the dovetail support member 1126. Any other conventionalvibration isolator can instead be used as desired.

It should be noted that the various manners described above foradjustably positioning the horizontal truss 110 (via the brackets 114 a,114 b, second horizontal trusses 214 a, 214 b, 1214 a, 1214 b, and thelike) apply equally to alternative embodiments of the present invention(e.g., in which no brackets 114 a, 114 b are employed or in which thevibrational device has no identifiable second horizontal trusses 214 a,214 b, 1214 a, 1214 b). In such cases, the ends of the horizontal truss110, 210 can be permanently or adjustably connected to differentlocations on the papermaking machine frame or to the ground.

A number of different elements and structures exist for adjusting theheight of the horizontal truss 110, 210 at either or both ends thereof.The jackscrew-type vertical adjustment mechanisms 120, 222 describedabove and illustrated in the figures are well-suited for brackets 114 a,114 b or second horizontal trusses on the ends of the truss 110, 210. Inother embodiments (whether employing brackets 114 a, 114 b, secondhorizontal trusses 214 a, 214 b, 1214 a, 1214 b or other structure), theends of the horizontal truss 110, 210 can be lifted and lowered by anyconventional jack mechanism, including without limitation by ratchet orscissor-type jacks connected between the papermaking machine frame orground and the truss, by conventional hydraulic, pneumatic, orelectrical jacks, by shims, by one or more bladders fillable with air orfluid, and the like. One having ordinary skill in the art willappreciate that still other examples of adjusting the height of thetruss 110, 210 are possible, each one of which falls within the spiritand scope of the present invention.

Preferably, the brackets 114 a and 114 b or second horizontal trusses214 a, 214 b, 1214 a, 1214 b also include a vibrational isolator (notshown) to isolate the machine frame 12 from any vibrations of thevibrational device 100, 200, 1200 and, likewise, to isolate thevibrational device 100, 200, 1200 from any vibrations of the papermakingmachine frame 12. In one highly preferred embodiment, the vibrationalisolator is a pad, block, or other element made from a compressible andvibration-damping material such as rubber, plastic, urethane, wool,cork, and the like positioned between steel blocks within the brackets114 a and 114 b or against the second horizontal trusses 214 a, 214 b,1214 a, 1214 b. In other embodiments, the vibrational isolator is an gasor fluid bag positioned within the brackets 114 a and 114 b or againstthe second horizontal trusses 214 a, 214 b, 1214 a, 1214 b. Vibrationisolators can also be used in those embodiments of the present inventionnot having brackets 114 a, 114 b or second horizontal trusses 214 a, 214b, 1214 a, 1214 b as described above. Any other conventional vibrationisolator can instead be used as desired.

Preferably, the vibrational device frame 102, 202, including thehorizontal truss 110, 210 and the diagonal trusses 112 a and 112 andbrackets 114 a and 114 b (if used) or the vertical and secondaryhorizontal truss structure (if used), is constructed of stainless steel.Most preferably, the vibrational device frame 102, 202 is constructed of316 stainless steel, because 316 stainless steel is largely inert to thecaustic and acidic environment of the papermaking machine.

The following description is with reference to the vibrational device100 illustrated in FIGS. 4 and 5 a, it being understood, however, thatthe various elements, structures, operational features, and alternativesdescribed below apply equally to the vibrational device embodimentillustrated in FIG. 5 b and 5 c.

With reference again to the embodiment of the present inventionillustrated in FIGS. 4 and 5 a, the vibrational device 100 preferablyincludes at least one vibration-inducing mechanism 104. More preferably,the vibrational device 100 includes multiple vibration-inducingmechanisms 104 positioned across the width (i.e. cross-machinedirection) of the wire 16. Preferably, the vibration-inducing mechanisms104 are coupled to the vibrational head 106, but not to the vibrationaldevice frame 102. As with the embodiment illustrated in FIG. 5 b, threevibration-inducing mechanisms 104 are preferably equally spaced acrossthe width of the wire 16 and are coupled to the vibrational head 106 viaa plurality of bolts 132. Other numbers and spacings of thevibration-inducing mechanisms 104 can be employed if desired. Thevibration-inducing mechanisms can be attached to the vibrational head106 in other manners, such as by rivets, pins, clips, clamps, nails,buckles, clasps, or other conventional fasteners, by welding, brazing,or adhesive, by threaded, snap-fit, or other inter-engaging connections,and the like.

In some preferred embodiments, one vibration-inducing mechanism 104 ispositioned every one to four feet across the width of the wire 16. Forexample, for a typical wire 16 having a width of 30 feet, preferably tenvibration-inducing mechanisms 104 are positioned across the width of thewire 16. The number of vibration-inducing mechanisms 104 positionedacross the width of the wire 16 is at least partially a function of thepower output of each vibration-inducing mechanism 104 and the physicalsize of each vibration-inducing mechanism 104. However, any number ofvibration-inducing mechanisms 104 could be positioned across the widthof the wire 16 in any suitable configuration.

The vibration-inducing mechanisms 104 are preferably any type ofpneumatic, hydraulic, electric, mechanical or electromagnetic mechanismsthat are able to impart a force having a relatively high frequency and arelatively low amplitude to the wire 16. Vibrators andvibration-inducing mechanisms driven pneumatically, hydraulically,electrically, mechanically, or eletro-mechanically are well-known tothose skilled in the art, and are not therefore described furtherherein. In some preferred embodiments, the vibration-inducing mechanisms104 each impart a force of approximately 20 to 7000 pounds with afrequency of approximately 20 to 2000 Hertz and an amplitude of up toapproximately 0.120 inches. However, superior results are achieved whenthe vibration-inducing mechanisms vibrate at a frequency of at least1,000 Hertz. Also, the amplitude of the vibrational force may beadjusted so that the vibrational head 106 has a range of vibrationalmovement and is in direct contact with the wire 16 in only part of therange of vibrational movement. In general, the heavier the weight of thepaper being produced and/or the faster the speed of the papermakingmachine, the greater the force necessary to vibrate the wire 16.However, the frequencies and amplitudes of the vibrational forcestransferred to the wire 16 are preferably independent of the speed atwhich the wire 16 is travelling (i.e., the papermaking machine speed).

In some embodiments, each one of the vibration-inducing mechanisms 104is controlled individually so as to impart different forces havingdifferent frequencies and/or different amplitudes to different sectionsof the wire 16 across the width (i.e., the cross-machine direction) ofthe wire 16. For example, a first vibration-inducing mechanism 104generates a first vibrational force having a first frequency, and asecond vibration-inducing mechanism 104 generates a second vibrationalforce having a second frequency different from the first frequency. Thefirst vibrational force is transferred to a first section of the wire 16in the cross-machine direction, and the second vibrational force istransferred to a second section of the wire 16 in the cross-machinedirection. The first and second vibrational forces may also havedifferent amplitudes. The frequency and amplitude of the firstvibrational force may be controlled independently of the frequency andamplitude of the second vibrational force, and vice versa, so that thefrequencies and amplitudes of the vibrational forces may be changedindependently during operation of the vibrational device 100, 200.Moreover, the frequencies and amplitudes of the different vibrationalforces transferred to the wire 16 in the cross-machine direction arepreferably each independent of the speed at which the wire 16 istraveling (i.e., the papermaking machine speed).

By varying the frequencies and amplitudes of the vibrational forcestransferred to different sections of the wire 16, the quality of thepaper web can be more precisely controlled in the cross-machinedirection. For example, the quality of the center of the paper web maybe acceptable, but the quality of the edges of the paper web may not beacceptable. In this case, the vibration-inducing mechanisms 104corresponding to the edges of the paper web may be adjusted to transfervibrational forces having higher frequencies and/or amplitudes to theedges of the wire 16. In addition, the vibration-inducing mechanisms 104corresponding to the center of the paper web may be adjusted to transfervibrational forces having lower frequencies and/or amplitudes to thecenter of the wire 16. Moreover, the vibration-inducing mechanisms 104corresponding to the center of the paper web may be turned off oradjusted to not transfer vibrational forces to the center of the wire16.

The type of vibration-inducing mechanisms 104 used in each applicationcould vary depending upon the type of power source available near thepapermaking machine. Each type of vibration-inducing mechanism 104 canbe implemented within the vibrational device 100 in the same manner.Most preferably, the vibration-inducing mechanisms 104 are pneumaticturbine vibrators manufactured by Vibco, Inc. of Wyoming, R.I. The mostpreferred Vibco pneumatic turbine vibrators for use as thevibration-inducing mechanisms 104 are series CCF-L-, W, V, BV, SVR, andHLF. The Vibco pneumatic turbine vibrators are manufactured under one ormore of the following patents, the disclosures of which are incorporatedherein by reference: U.S. Pat. Nos. 3,870,282; 3,932,057; 3,938,905;4,389,120; and 4,424,718 insofar as they relate to vibrator devices,their structure, and operation.

The vibrational device 100 illustrated FIGS. 5 a and 5 c is describedabove as having pneumatic vibration-inducing mechanisms by way ofexample only. As also described above, the vibration-inducing mechanismscan take a number of other forms. With reference to FIGS. 5 a and 5 c,fluid or gas (preferably air) is preferably supplied via a plurality oflines 170 to the pneumatic vibration-inducing mechanisms 104. Theplurality of air lines 170 can be coupled to the horizontal truss 110,if desired. In one preferred embodiment, the plurality of air lines 170are coupled to an air supply through a flow meter 172, a regulator 174,and a valve 176 in order to control the pressure and rate of the airsupplied to the pneumatic vibration-inducing mechanisms 104. Otherconventional pneumatic systems can instead be used to also control thepressure, rate, and volume of the air supplied to the pneumaticvibration-inducing mechanisms 104. In one preferred embodiment, air issupplied to the pneumatic vibration-inducing mechanisms 104 atapproximately 80 pounds per square inch and 40 cubic feet per minute.One skilled in the art will recognize that other air supply pressures,rates, and volumes could be used to generate suitable vibrationalforces, each one of which falls within the spirit and scope of thepresent invention. Preferably, the vibration-inducing mechanisms 104each include a conventional solenoid valve (not shown) coupled to theair supply lines 170 in a conventional manner. The solenoid valvepreferably regulates the amplitude and frequency of thevibration-inducing mechanisms 104, thus regulating the amplitude andfrequency of the vibrational head 106 itself.

FIG. 5 d illustrates another vibration-inducing mechanism 604 accordingto the present invention. The vibration-inducing mechanism 604 of FIG. 5d is an electromagnetic, vibration-inducing mechanism having atactile-sound transducer. The transducer uses a magnet structure toproduce a force output per energy input over a wide range of frequencies(e.g., 15 Hertz-17,000 Hertz), although superior results can be obtainedat frequencies over 1,000 Hertz. Using this type of vibration-inducingmechanism 604, the amplitude and the frequency of the output can beeasily controlled for each individual vibration-inducing mechanism 604.Preferably, the vibration-inducing mechanism 604 operates at a frequencyindependent of the speed at which the wire 16 is traveling (i.e.,machine speed). If desired, one or more conventional electronicamplifiers (not shown) can be used to control the rate of vibration ofeach independent vibration-inducing mechanism 604 or for all of thevibration-inducing mechanisms 604 in series.

Referring again to the illustrated preferred embodiment of FIGS. 5 a and5 c, the vibrational device 100 includes at least one vibration isolator105 coupled between the horizontal truss 110 and the vibrational head106, although such an isolator is not required to practice the presentinvention. More preferably, the vibrational device 100 includes aplurality of vibration isolators 105 coupled in this manner. Theplurality of vibration isolators 105 at least partially isolate thevibrational device frame 102 from the vibrations generated by thevibration-inducing mechanisms 104. The vibration isolators 105 can bepositioned in any manner in the vibrational device 100. Preferablyhowever, one vibration isolator 105 is positioned on either side of eachvibration-inducing mechanism 104. In the highly preferred embodimentillustrated in FIGS. 5 a and 5 c, four vibration isolators 105 arepositioned along the horizontal truss 110 on either side of the threevibration-inducing mechanisms 104. Other vibration isolator arrangementsare possible. With reference to the embodiment of the present inventionillustrated in FIG. 5 b for example, multiple vibration isolators 205can be positioned along the horizontal truss 210 on either side of thevibration-inducing mechanisms 204 in order to further increase machinedirection stability for the vibrational device 200.

With reference to both illustrated preferred embodiments of the presentinvention illustrated in FIGS. 5 a-5 b, the vibration isolator 105, 205is preferably coupled between the horizontal truss 110, 210 and thevibrational head 106, 206 (see FIGS. 7 a-7 c). The vibration isolator105, 205 preferably includes an upper bracket 134, 234 coupled to thevibrational head 106, 206, a lower bracket 136, 236 coupled to thehorizontal truss 110, 210 via bolts 138, 238, and an air bag 140, 240coupled between the upper bracket 134, 234 and the lower bracket 136,236. A fluid or a gas (preferably air) is supplied to the bag 140, 240via a hose 142, 242 coupled to an air source (as shown in FIGS. 5 a and5 b). Air supplied to the air bag 140, 240 is regulated to keep the airbag 140, 240 at a pressure high enough to absorb vibrational frequenciesgenerated by the vibration-inducing mechanisms 104, 204 and to supportthe vibrational head 106, 206, but low enough so as not to impart anadditional force to the vibrational head 106, 206. In some preferredembodiments, the air bag 140, 240 is kept at a gauge pressure of 5 to 20pounds per square inch. In some highly preferred embodiment, the air bag140, 240 is also used to control the height of the vibrational head 106,206 by varying the input air pressure to the air bag 140, 240. Also insome highly preferred embodiments, each air bag 140, 240 isindependently supplied with air pressure such that the height of thevibrational head 106, 206 can be adjusted differently at variouspositions across the width of the wire 16.

The vibration isolators 105, 205 can be connected to the vibrationalhead 106, 206 and to the horizontal truss 110, 210 in a number ofdifferent manners, including those described above with reference to theconnection between the vibration-inducing mechanisms 104, 204 and thevibrational head 106, 206.

Although the vibration isolators 105, 205 are preferably air bagvibration isolators, one having ordinary skill in the art willappreciate that other types of vibration isolators can instead beemployed. For example, other vibration isolators include withoutlimitation pneumatic springs and shocks, hydraulic springs and shocks,electromagnet sets, solenoids, torsion, extension, compression, leaf,and other springs, and the like connected in a manner similar to the airbag vibration isolators described above. While any of these types ofvibration isolators can be used to dampen vibrations as also describedabove, controllable vibration isolators are most preferred to enable theuser to control the amount of vibration damping provided by thevibration isolators. Controllable vibration isolators and theiroperation are well known to those skilled in the art and are nottherefore described further herein.

With particular reference to FIGS. 7 a-7 c, the vibrational device frame102, 202, the vibration-inducing mechanisms 104, 204, and thevibrational isolators 105, 205 are preferably covered with a sheathingmaterial 180, 280 suitable for protecting the internal components of thevibrational device 100, 200 and for providing a smooth surface, free ofrecesses, corners, and protrusions. In most preferred embodiments, thevibrational head 106, 206 is the only component of the vibrationaldevice 100, 200 that is not sheathed. Most preferably, the sheathingmaterial 180, 280 is a thin-gauge stainless steel that drapes over thevibrational device 100, 200 and is welded onto the vibrational deviceframe 102, 202 or is connected thereto in any other conventional manner.However, the sheathing material 180, 280 can be any type or combinationof materials compatible with the papermaking process that do not degradefrom the chemicals used in the papermaking process and that do notcontaminate the papermaking process.

As shown in FIG. 7 a-7 c, the vibrational head 106, 206 preferablyincludes a sliding mechanism 148, 248 and a vibrational element 150, 250coupled to the sliding mechanism 148, 248 for engaging the wire 16. Thesliding mechanism 148, 248 can be connected to the vibrational element150, 250 in a number of different manners, such as via one of thesliding connections shown in FIGS. 7 a-7 c. In FIG. 7 a for example, thesliding mechanism 148 preferably has a male dovetail configuration,including a horizontal engagement surface 152 and two diagonalengagement surfaces 154 a and 154 b. The sliding mechanism 148 isconnectable to a female dovetail configuration 156 in the bottom surface158 of the vibrational element 150 (although the locations of thedovetail shapes can be reversed in other embodiments). Alternatively,the vibrational head 206 can have one or more sliding mechanisms havinga T, L, I, or other mating shape. In FIGS. 7 b and 7 c, the vibrationalhead 206 includes a sliding mechanism 248 having a T-slot configuration.The sliding mechanism 148, 248 can have any other configuration suitablefor slidably coupling the vibrational element 150, 250 to the solenoidvalves of the vibration-inducing mechanisms 104, 204. The slidingmechanism 148, 248 allows the vibrational element 150, 250 to be removedfrom the vibrational device 100, 200 and to be replaced, preferably evenwhile the papermaking machine is operating.

In other embodiments of the present invention, the vibration-inducingmechanisms 104, 204 can be releasably connected to the vibrationalelement 150, 250 in other manners. For example, the vibration-inducingmechanisms 104, 204 can be releasably connected to the vibrationalelement 150, 250 by one or more conventional fasteners including one ormore bolts, pins, clips, and the like, by one or more tongue and groovejoints, by a flange, boss, bracket, rail, or other element or extensionon the vibration-inducing mechanisms 104, 204 received within one ormore grooves, slots, or other apertures in the vibrational element 150,250 (and vice versa), and the like. In embodiments where a removablevibrational element 150, 250 is not needed or desired, the vibrationalelement 150, 250 can be permanently connected to the vibration-inducingmechanisms 104, 204 in any conventional manner desired.

The vibrational element 150, 250 can have any shape and size. However,in some highly preferred embodiments, the vibrational element 150, 250has a width of approximately one to ten inches and a lengthapproximately equal to the width of the wire 16 in the cross-machinedirection. The vibrational element 150, 250 preferably has a land area160, 260 at the plane of intersection with the wire 16. The land area160, 260 is the area through which the vibrational force is transferredfrom the vibrational element 150, 250, through the bottom of the wire16, and into the web being transported by the wire 16.

In one highly preferred embodiment of the present invention shown inFIG. 8 a, the vibrational element 150 (referring to the illustratedpreferred embodiment of FIGS. 4, 5 a, 7 a, and 7 b by way of exampleonly) has a land area 160 with an upstream portion 162 and a downstreamportion 164. The upstream portion 162 preferably slopes verticallydownward from the wire 16 at a lead angle β of approximately 0 to 15degrees. The lead angle β of the upstream portion 162 of the vibrationalelement 150 preferably pushes water up into the wire 16 when thevibrational element 150 engages the underside of the wire 16. Thedownstream portion 164 preferably slopes vertically downward from thewire 16 at a relief angle φ of approximately 0 to 5 degrees. The reliefangle φ of the downstream portion 164 of the vibrational element 150preferably induces a vacuum when the vibrational element 150 engages theunderside of the wire 16. In another highly preferred embodiment of thevibrational element 150 shown in FIG. 8 b, the land area 160 has aconvex configuration having a radius R of approximately 4 to 8 inches.

The vibrational element 150, 250 can have any configuration suitable forengaging the underside of the wire 16 and imparting a vibrational forceto the underside of the wire 16. In particular, as shown in FIGS. 8 c-8e, the vibrational element 150, 250 can have a generally flatconfiguration similar to the stationary foils 36. Also, the vibrationalelement 150, 250 can have various machine-direction lengths (e.g., along length as shown in FIG. 8 c, a medium length as shown in FIG. 8 b,and a short length as shown in FIG. 8 c). Alternatively, the vibrationalelement 150, 250 can have any cross-sectional shape and anymachine-direction length desired which is capable of transmittingvibrational force to the underside of the wire 16, including withoutlimitation rectangular, round, oval, concave, convex, wave, andirregular shapes. The cross-sectional shapes need not necessarily havesloping upstream or downstream portions as described above withreference to the vibrational elements 150 shown in FIGS. 8 a and 8 b.

A vibrational element 150, 250 partially or fully spanning the wire 16in the machine direction and actuated by one or more vibration-inducingmechanisms 104, 204 is preferred. However, vibration can be transmittedto the wire 16 from the vibration-inducing mechanisms 104, 204 in avariety of different manners. The vibration-inducing mechanisms 104, 204can press directly against the underside of the wire 16 (e.g., atmultiple points across the wire 16), can actuate separate elements inconstant or intermittent contact with the underside of the wire 16, andthe like. In those embodiments not having a vibrational element to whichthe vibration-inducing mechanisms 104, 204 can be suspended or otherwisesupported, the vibration-inducing mechanisms 104, 204 can be mountedupon a rail, bar, plate, frame, or other structure located beneath thewire 16.

The manner in which the vibration-inducing mechanisms 104, 204 exertvibrational force to the underside of the wire 16 depends at leastpartially upon the type of vibration-inducing mechanisms being used. Forexample, many conventional vibration-inducing mechanisms have baseplates through which generated vibration is transmitted. Thesevibration-inducing mechanisms can be employed in the vibrational device100, 200 of the present invention, and can be mounted on a frame orother structure so that their bases are in direct or indirectvibration-transmitting contact with the underside of the wire 16. Asanother example, one or more solenoids having extendible armatures canbe mounted across the underside of the wire 16 so that the armatures canextend into contact with the underside of the wire 16 when the solenoidsare actuated. As yet another example, a shaft having multiple camsthereon can be rotatably mounted across the underside of the wire 16 sothat rotation of the shaft causes the cams to come into repeated contactwith the wire 16 to vibrate the wire 16.

The vibrational device 100, 200 can include two or more independentvibrational heads 106, 206 mounted to a single vibrational device frame102, 202 (see FIG. 5 b, for example). Each independent vibrational head106, 206 can have independent vibration-inducing mechanisms 104, 204coupled to the single vibrational device frame 102, 202 and one or morevibrational isolators 105, 205 mounted between the vibrational heads106, 206 and the vibrational device frame 102, 202. For example, asshown in FIG. 5 b, three vibrational heads 206 are coupled to thevibrational device frame 202. Each one of the three vibrational heads206 may transfer a different vibrational force to a different section ofthe wire 16 by independently controlling the frequencies and amplitudesof the vibrational forces generated by each one of the threevibration-inducing mechanisms 204. One having ordinary skill in the artwill appreciate that still other manners of transmitting vibrationalforce to the underside of the wire 16 are possible and can be employedas alternatives to the preferred vibrational element 150, 250,vibration-inducing mechanisms 104, 204, and horizontal truss 110, 210described above and illustrated in the figures. Each of thesealternatives is considered to fall within the spirit and scope of thepresent invention.

Preferably, the vibrational head 106, 206 is a rigid structure capableof transferring a consistent vibrational force from thevibration-inducing mechanism 104, 204 to the vibrational element 150,250. The vibrational head 106, 206 can be constructed of any materialdesired, and is preferably constructed of a relatively rigid materialsuch as steel, fiberglass, composites, or combinations thereof. Thevibrational head 106, 206 can include plates, angles, tubes, honeycombor mini-truss elements, or other structural members fastened to thevibrational isolators 105, 205 or the papermaking machine frame 12 inany conventional manner, such as by welding, brazing, pinning,laminating, or bolting. One having ordinary skill in the art willappreciate that still other examples of materials and designs for thevibrational head 106, 206 are possible.

The vibrational element 150, 250 can be constructed of any material thatis preferably less abrasive than the material of the wire 16.Preferably, the vibrational element 150, 250 is constructed of materialthat wears well, in addition to being less abrasive than the material ofthe wire 16. Most preferably, the vibrational element 150, 250 isconstructed of ultra-high, molecular-weight (UHMW) polyethylene.

As best shown in the illustrated preferred embodiment of FIGS. 1 and 2,in addition to the vibrational devices 100, some highly preferredembodiments of the present invention include one or more lubricationshowers 121 positioned upstream from the vibrational device 100. Thelubrication shower 121 preferably spans the entire cross-machinedirection width of the wire 16. The lubrication shower 121 directs waterinto the pinch point (i.e., the nip) caused when the vibrational element150 engages the underside of the traveling wire 16. Preferably, thelubrication shower 121 includes a water pipe, tube, chamber, or otherconduit and a plurality of fan-type nozzles (not shown) connectedthereto for injecting a sufficient amount of water so as to act as anon-compressible media capable of penetrating through the wire 16 andinto the web. In some preferred embodiments, the lubrication shower 121includes high-pressure needle showers that oscillate with a sufficientspray pattern to cover the entire width of the wire 16. The water fromthe lubrication shower 121 minimizes the premature wear of both the wire16 and the vibrational element 150 by minimizing the friction betweenthe two. In some highly preferred embodiments, the water supplied by thelubrication shower 121 carries the vibrational energy from thevibrational element 150, through the wire 16, and into the stock flow.

According to the method of the invention, the vibrational device 100,200 is used to impart a vibrational force to the underside of the wire16 in order to create turbulence within the stock flow. Preferably, thisvibrational force is a high frequency, low amplitude force. Creatingturbulence within the stock flow keeps the fibers within the stock flowin free suspension, i.e., prevents the fibers from bonding to oneanother, for a longer period of time. Preferably, sufficient turbulenceis created to cause the free suspension of fibers having a length offrom approximately 0.5 mm to approximately 12 mm. In order to excite andre-align the fibers, the fibers preferably must be moved a distanceequal to at least their length. Thus, sufficient turbulence is createdto move the fibers approximately 0.5 mm to approximately 12 mm. Duringthis added time of free suspension or re-fluidization, the fibers areable to re-align with respect to one another. Once the fibers begin tobond to one another after being re-aligned, the fibers re-settle on thewire 16 in a more uniform pattern and penetrate into empty voids inwhich fibers had not yet settled. This resettling of the fibers resultsin more consistent fiber distribution in the cross-machine direction,the machine direction, and the Z direction.

High levels of turbulence, although beneficial for good formation, canresult in the low retention of fines and fillers in the web due to thedisruption of the matted web. However, inter-slurry fiber collisions andcollisions between fibers and the wire 16 which occur in increasedstates of turbulence can have a beneficial influence on the retention offines and fillers within the web. In addition to creating turbulencewithin the stock flow, the vibrational force imparted to the undersideof the wire 16 by the vibrational device 100, 200, along with the waterdelivered by the lubrication shower 121, helps to release boundary layerfibers that may have become impregnated in the wire 16 due to thedelivery of the stock flow to the wire 16 at the angle of impingement α,especially in a pressure forming arrangement of the headbox 14.

As shown in FIG. 9 a, when a vibrational force is not imparted to thewire 16, the fibers within the stock flow begin to bond to one anotherand settle on the wire 16 in a non-uniform manner as water drainsdownwardly through the wire 16. The bottom-most layers of fibers 300 aremuch more dense than the upper-most layers of fibers 302. In addition,the upper-most layers of fibers 302 often lack moisture, due to waterdraining downwardly through the wire 16. As shown in FIG. 9 b, when avibrational force is imparted to the wire 16 by the present invention,the fibers settle on the wire 16 in a more uniform pattern. In addition,the bottom-most layers of fibers 300 are more uniform in density withthe upper-most layers of fibers 302 because the fibers re-settle on thewire 16 filling empty voids as the web forms.

In either a pressure forming or a velocity forming arrangement of theheadbox 14, water removal and boundary layer fiber bonding normallycommences as soon as the stock flow contacts the wire 16. Thevibrational device 100, 200 therefore preferably imparts vibrationalforce to the underside of the wire 16 before an embryonic web issubstantially formed. If the vibrational device 100, 200 imparts thevibrational force to the underside of the wire 16 after the embryonicweb has substantially formed, the vibrational force may damage ordestroy the web. Accordingly, some embodiments of the present inventionemploy the vibrational devices 100, 200 are preferably positioned withinthe papermaking machine wet-end section 10 so that the vibrationalforces are imparted to the wire 16 before a significant amount of wateris removed from the stock flow as distributed by the headbox 14 andbefore significant formation of the embryonic web. The stock flowdistributed onto the wire 16 by the headbox 14 is preferably 99 percentwater and 1 percent fibers, although stock flows having differentconsistencies can be used. Preferably, the vibrational devices 100, 200are positioned within the papermaking machine wet-end section 10 so thatvibrational forces are imparted to the wire 16 before the web has afiber consistency of 5 percent and a water consistency of 95 percent,i.e., during the formation of the embryonic web.

Moreover, the lubrication shower 121 (if used) preferably injects asufficient amount of water into the wire 16 so as to act as anon-compressible media that reduces wear of both the vibrational element150, 250 and the wire 16. The water injected by the lubrication shower121 is preferably capable of penetrating through the wire 16 and intothe web to help release boundary layer fibers impregnated in the wire 16and to help maintain the free suspension of the fibers (i.e., aid inre-fluidization) in order to prevent or at least delay the formation ofthe embryonic web.

In some preferred embodiments of the present invention, at least onevibrational device 100, 200 is installed within the wet-end section 10of an existing papermaking machine. The vibrational devices 100, 200 inthe illustrated preferred embodiments of FIGS. 1-8 e are preferablyinstalled into the papermaking machine wet-end section 10 by sliding thefemale dovetail configuration of the vertical adjustment mechanism 120,222 over the male dovetail support member 126 of the papermaking machineframe 12. Preferably, if more than one vibrational device 100, 200 isinstalled, the vibrational devices 100, 200 are separated by at leastone foil box 32, and thus, a plurality of stationary foils 36. Mostpreferably, a first vibrational device 100, 200 is positioned betweenthe initial forming board 30 and the first of the plurality of foilboxes 32 and a second vibrational device 100, 200 is positioned betweenthe second of the plurality of foil boxes 32 and the third of theplurality of foil boxes 32. However, any number of vibrational devices100, 200 of the present invention can be installed at any location alongthe wet-end section 10 of the papermaking machine and between any of thestationary foils or forming boards along the wet-end section 10.

If additional dwell time is required for formation of the web after thevibrational device 100, 200, auxiliary forming boards (not shown) can beinstalled downstream from the vibrational device 100, 200. The auxiliaryforming boards can replace some of the plurality of stationary foils 36or can be added to the papermaking machine wet-end section 10 inaddition to the plurality of stationary foils 36. Auxiliary formingboards or the plurality of stationary foils 36 can also be an integralpart of the vibrational device 100, 200 itself. In addition, existingforming boards 30 can be modified to incorporate the principles of thevibrational device 100, 200 of the present invention.

In some preferred embodiments, after the vibrational device 100, 200 isinstalled, the vertical orientation of the vibrational device 100, 200with respect to the wire 16 can be adjusted. In order to adjust thevertical orientation in the illustrated preferred embodiment, anoperator rotates the adjustment nut 130, 230 of the vertical adjustmentmechanism 120, 222. The adjustment nut 130, 230 adjusts the threaded rod128 a, 224 a in the threaded aperture 128 b, 224 b of the horizontaltruss 110, 210, thereby raising or lowering the horizontal truss 110,210 with respect to the papermaking machine frame and the wire 16.

Preferably, the vertical orientation of the vibrational device 100, 200is adjusted until the vibrational element 150, 250 engages the undersideof the wire 16. Most preferably, the vertical orientation of thevibrational device 100, 200 is adjusted until the vibrational element150, 250 raises the wire 16 by approximately 0.001 to 0.002 inches.However, the vibrational device 100, 200 can be adjusted so that thevibrational element 150, 250 does not actually contact and engage thewire 16. Also, the vertical orientation of the vibrational device 100,200 may be adjusted so that the vibrational head 106, 206 has a range ofvibrational movement and is in direct contact with the wire 16 in onlypart of the range of vibrational movement. One skilled in the art willrecognize that the vertical adjustment of the vibrational device 100,200 can depend on the grade of paper being produced or the papermakingmachine speed. Although adjustment of the vertical orientation of thevibrational device 100, 200 as described above and shown in the drawingsis through the use of a threaded rod and aperture connection, thevertical orientation of the vibrational device 100, 200 can be adjustedwith any type of vertical adjustment mechanism or elevator as describedabove. Moreover, the vertical orientation of the vibrational device 100,200 can be adjusted manually, if desired.

Once the vibrational device 100, 200 is installed and the verticalorientation with respect to the wire 16 is adjusted, the vibrationalforce generated by the plurality of vibration-inducing mechanisms 104,204 is preferably modified depending on the type of paper being producedand the operating speed of the papermaking machine. The operating speedof the papermaking machine, i.e. the velocity of the web, is often from100 feet per minute to 5000 feet per minute. The vibrational force ispreferably adjusted until sufficient turbulence is created in the stockflow to create free suspension of the fibers and sufficient re-alignmentof the fibers as described in greater detail above. The vibrationalforce is preferably varied by altering the input to the plurality ofvibration-inducing mechanisms 104, 204. In some highly preferredembodiments, each one of the plurality of vibration-inducing mechanisms104, 204 can be controlled independently in order (i.e., controllingvibration frequency and/or amplitude) to impart different forces todifferent portions of the cross-machine direction width of the wire 16.Imparting different forces to different portions of the wire 16 allowsthe amount of fiber re-alignment to be varied across the width of thewire 16. The control of the input to the vibration-inducing mechanisms104, 204 is preferably integrated in a closed loop with a conventionaldigital control system for the papermaking machine.

Whether the vibrational force imparted to the wire 16 by the vibrationaldevice 100, 200 is sufficient is determined by testing the web solidsoff of the couch roll 24 and press section and sheet samples from thereel section. Typical testing of the sheets includes visual inspection,internal bond, opacity, tear (tensile strength), and crush (compressivestrength), smoothness, and any other standardized testing as stipulatedby the Technical Association of the Pulp and Paper Institute (TAPPI).Applying a harmonic vibrational force to the web generally improvesembryonic web formation and sheet properties with no deterioration offirst pass retention, i.e., the fiber, fine, and filler content in theweb is not lost. In addition, the phenomena of two-sidedness in thesheet is reduced, since the fiber distribution within the sheet isimproved and boundary layer fibers are released from being impregnatedin the wire 16.

Sheet profiles, i.e. the characteristics of the sheet in the machinedirection, the cross-machine direction, and the Z direction, aregenerally improved when a harmonic vibrational force is applied to theweb as performed in the present invention. Sheet profile characteristicsthat are generally improved by applying a harmonic vibrational force tothe web are strength, sheet weight, moisture content, and solid content.In particular, tensile strength in the machine direction is improved.Sheet properties are improved due to the more consistent re-aligning andre-settling of the fibers into empty voids. As shown in FIG. 10, sheetproperties are often plotted versus the cross-machine direction (i.e.,width) of the sheet. Ideally, the sheet properties would be constantacross the width of the sheet as represented by line 400. However, theactual sheet properties generally vary across the width of the sheet asrepresented by plot 402. Applying a harmonic vibrational force to theweb helps to make the sheet properties of the web more constant acrossthe width of the sheet in order to approach line 400. Improvements insome sheet properties lead to faster machine speeds and less web breaksthroughout the papermaking process, resulting in a substantial costsavings due to higher production rates.

The use of the vibrational device 100, 200 in the papermaking machinewet-end section 10 results in more water being drained from the web in amore efficient manner. As a result, some of the plurality of stationaryfoils 36 can be eliminated from the wet-end section 10. Moreover, sincewater drains more efficiently from the web, the energy required to drythe web in the dryer section of the papermaking machine is reduced.Since water removal is one of the most energy-intensive operations inthe industrial papermaking process, a reduction in the energy necessaryto dry the web results in a substantial reduction in operating costs.

It should be noted that a vibrational device 100, 200 can be installedbeneath the papermaking machine frame 12 so that the vibrational device100, 200 engages the wire 16 as the wire 16 returns to the headbox 14.In this configuration, the vibrational device 100, 200 positionedbeneath the papermaking machine frame 12 acts as a wire-cleaningmechanism as the wire 16 is returned to the headbox 14.

Once the vibrational device 100, 200 has operated within the papermakingmachine wet-end section 10 for an extended period of time, thevibrational element 150,250 may become worn due to constant abrasionfrom engaging the wire 16. When the vibrational element 150, 250 becomesworn, the vibrational element 150, 250 can preferably be replaced eitherwhile the papermaking machine is operating or when the papermakingmachine is not operating. Since the vibrational element 150, 250 ispreferably coupled to the vibrational isolators 105, 205 and thevibrational head 106, 206 via a sliding mechanism 148, 248, thevibrational element 150, 250 can preferably be slid off of the slidingmechanism 148, 248 and removed from the vibrational head 106, 206.Similarly, a replacement vibrational element 150, 250 can be slid backonto the sliding mechanism 148, 248, even during operation of thepapermaking machine.

Although the vibrational device 100, 200 of the present inventionprovides significant advantages in the papermaking process when used inthe wet-end section 10 of a papermaking machine (as described above),the vibrational device 100, 200 can also be employed in the presssection of a papermaking machine for improved operation thereof. It isimportant to note that above discussion regarding the structure andoperation of the vibrational device 100, 200 in the wet-end section 10of the papermaking machine (as shown and described with respect to FIGS.1-10) applies equally when the vibrational device 100, 200 is employedin the press section of the papermaking machine.

As shown schematically in FIG. 11, a press section 500 follows thewet-end section 10 of a papermaking machine, and precedes a dryersection 600. The papermaking machine press-section 500 preferablyincludes press rolls 502, return rolls 504, press felts 506, and suctiondevices 508. The paper web is preferably transferred from the wet-endsection 10 to the press-section 500 via a suction pick-up roll 510. Thepaper web travels between the press felts 506 and is carried throughnips created by press rolls 502, which mechanically squeeze water fromthe paper web.

The press felt 506, which may also be referred to simply as the “felt,”is preferably a moving, endless belt of cotton mesh fabric. Preferably,the press felt 506 is movably coupled to the papermaking machine frame12 via several rolls in a manner that provides an endless conveyor beltfor receiving and transporting the paper web delivered from the papermachine wet-end section 10. The press felt 506 first wraps around thepick-up roll 510, (which is preferably positioned adjacent to the couchroll 24), stretches from the pick-up roll 510 through the nip created bypress rolls 502, wraps partially around the press rolls 502, andstretches around the return rolls 504 to return to the pick-up roll 510.One having ordinary skill in the art will appreciate that the press felt506 can be driven about other elements in an endless-conveyorarrangement, such as by being passed around one or more sprockets,pulleys, or other preferably rotatable elements.

As shown in FIG. 13, the press felt 506 is preferably a multi-layeredwoven cotton or nylon-fiber mesh cloth that permits easy waterabsorption, yet provides sufficient strength and support so as not tomark or crush the paper web through the mechanical press. Although awoven cotton or nylon-fiber mesh cloth is preferred, any conventionalfelt material can be used as desired. As also shown in FIG. 13, in someembodiments a plurality of main strands 512 and a plurality ofconnecting strands 514 are woven together to form the base of the pressfelt 506. The plurality of main strands 512 and the plurality ofconnecting strands 514 can be made of finely drawn and woven, nylon, orcan be made of other conventional materials, such as polyamide-basedmaterials. A batt 516 is prepared in layers and needled onto theplurality of main strands 512 and the plurality of connecting strands514. One of ordinary skill in the art will appreciate that the weavepattern of the press felt 506 can have a single, double, triple, or anyother layer design. The press felt 506 is preferably not a permanentpart of the press section 500 and can be replaced in a conventionalmanner.

As shown in FIGS. 11 and 12, suction devices 508 are preferably employedto remove as much water as possible from the press felts 506, leavingclean and porous press felts 506. In the preferred embodiment shown inFIG. 12, the suction devices 508 include uhle boxes 518. Uhle boxes 518are elongated boards having a flat, top-side cover positioned on oneside of the press felt 506. A vacuum source (not shown) is supplied tothe uhle boxes 518 to generate a vacuum in order to pull water throughthe press felt 506. The vacuum created by the uhle boxes 518 preferablyalso pulls fines, fillers, and fibers that have become embedded from thepress felt 506. A lubrication shower 121 can be positioned within thepress section 500 upstream from the suction devices 508 in order tolubricate the underside of the press felt 506 to aid in removing fines,fillers, and fibers. If desired, alternative types of suction devices508 can be used as desired to clean the press felt 506.

In the press section 500, the vibrational device 100 and the waterdelivered by the lubrication shower 121 help release boundary layerfibers, fines, and fillers that may have become impregnated in the pressfelt 506 due to the paper web being mechanically pressed into the pressfelt 506. Thus, the use of the vibrational device 100 in the presssection 500 results in a cleaner press felt 506 and more efficient waterremoval from the paper web.

FIGS. 14 a-16 illustrate a vibrational device 1000 which is analternative embodiment of the vibrational devices 100 and 200 describedabove. Elements and features of the vibrational device 1000 illustratedin FIGS. 14 a-16 having a form, structure, or function similar to thatfound in the vibrational devices 100 and 200 of FIGS. 1-8 e, 11 and 12are given corresponding reference numbers in the 1000 series. With theexception of mutually exclusive features and elements between theembodiment of FIGS. 1-8 e, 11 and 12 and the embodiment of FIGS. 14a-16, reference is hereby made to the earlier embodiments for a morecomplete description of the features, elements (and alternativesthereto) of the embodiment illustrated in FIGS. 14 a-16 and describedbelow.

As shown in FIG. 15, the illustrated exemplary vibrational device 1000includes a vibrational device frame 1102 mountable to the papermakingmachine frame 1012 (or to other positions inside or adjacent thepapermaking machine frame 1012), one or more vibration-inducingmechanisms 1104 coupled to the vibrational device frame 1102, avibrational head 1106 coupled to the vibration-inducing mechanisms 1104,and one or more vibration isolators 1105 coupled between the vibrationalhead 1106 and the vibrational device frame 1102.

With reference again to the embodiment of the present inventionillustrated in FIGS. 14 a-16, the vibrational device 1000 can includemore than one vibration-inducing mechanism 1104. For example, thevibrational device 1000 can include multiple vibration-inducingmechanisms 1104 positioned across the width (i.e., the cross-machinedirection) of the wire (not shown). In some embodiments, thevibration-inducing mechanisms 1104 are coupled to the vibrational head1106, but are not mounted to the vibrational device frame 1102. In theillustrated exemplary embodiment of FIGS. 14 a-16, fourvibration-inducing mechanisms 1104 are spaced across the width of thewire and are be coupled to the vibrational head 1106. As discussed inthe earlier-described embodiments, any number of vibration-inducingmechanisms 1104 can be positioned in any manner (e.g., substantiallyequally spaced or in any other manner desired). Accordingly, othernumbers and spacings of vibration-inducing mechanisms 1104 can beemployed in order to span the cross-machine width of the wire.

In some embodiments, one or more of the vibration-inducing mechanisms1104 are controlled individually so as to adjust the frequencies, phasesand/or amplitudes of the vibrational forces transmitted from thevibration-inducing mechanisms 104 to different sections of the wire(i.e., different sections along the cross-machine direction of thewire). When the vibrational device 1000 includes more than onevibration-inducing mechanism 1104, it is often desirable to provide asmuch of a consistent vibrational output (in frequency, phase andamplitude) as possible along the entire cross-machine direction of thewire. In other words, it is desirable in some cases for web to have asubstantially flat displacement profile in the cross-machine direction.However, when more than one vibrational force is provided to thevibrational head 1106 (e.g., by multiple vibration-inducing mechanisms1104), the vibrational head 1106 can exhibit multiple modes ofvibration. In other words, the vibrational head 1106 can exhibitalternating high and low amplitude sections, in some cases following asinusoidal pattern of movement. This response from multiple vibrationalforces can result if the vibrational head 1106 is not adequately rigidin comparison to its weight, although other variables contribute to sucha response.

In some embodiments, the vibrational head 1106 includes one or morevibrational elements 1150 and one or more support members 1151. Severalsupport members 1151 can be connected in order to accommodate thecross-machine width of the wire. In some embodiments, each supportmember 1151 is coupled to a different vibrational element 1150. If thesupport members 1151 and the corresponding vibrational elements 1150 arerelatively short in length, the period of the vibrational response canbe increased until the displacement profile of the vibrational device1000 in the cross-machine direction is approximately flat. However, ifeach support member 1151 is coupled to one or more different vibrationalelements 1150, the paper web may exhibit one or more streaks produced bythe mismatched phase of adjacent support members 1151. To address thisproblem and/or other problems, a vibrational element 1150 can be mountedto adjacent support members 1151 (whether mounted to and spanning acrossthe entire length of the adjacent support members 1151 or any fractionthereof) as will be described in greater detail below.

When the vibrational head 1106 includes multiple support members 1151, afeedback control system can be used to coordinate the frequenciesprovided to each support member 1151 by the vibration-inducingmechanisms 1104. In some embodiments, the feedback control system cancontrol each support member 1151 independently by controlling thevibration-inducing mechanism(s) 1104 corresponding thereto. By way ofexample only, the frequency output of the vibration-inducing mechanisms1104 in some embodiments can be controlled by the speed of pneumaticvibrator motors 1104 connected thereto.

The feedback control system (if employed) can utilize a master frequencyset point for the vibration-inducing mechanisms 1104 and thecorresponding support members 1151. For example, the feedback controlsystem in some embodiments can control the vibration-inducing mechanisms1104 (and the corresponding support members 1151) to within ±0.1 Hz ofeach other or within ±0.1 Hz of a master frequency set point. Thefeedback control system can include an accelerometer coupled to eachsupport member 1151 in order to measure the frequency of each supportmember 1151. The accelerometer can send a signal to a programmable logiccontroller (PLC) or any other suitable controller or processor, whichcan respond to such signals by adjusting the speed of thevibration-inducing mechanisms (e.g., by adjusting pneumatic flow valvesof pneumatic vibration-inducing mechanisms 1104) connected to any givensupport member 1151.

The feedback control system can control the frequency of all supportmembers 1151 included in the vibrational head 1106, such as byseparately controlling each vibration-inducing mechanism 104 and/or byseparately controlling groups of vibration-inducing mechanisms (e.g.,groups of two or more vibration-inducing mechanisms 104 on a supportmember 1151). However, regardless of the ability to control the speed atwhich each vibration-inducing mechanism 104 (or group ofvibration-inducing mechanisms 104) operates, it can be difficult tocontrol and coordinate the phases of adjacent support members 1151 ofthe vibrational head 1106. For example, each support member 1151 can becontrolled to operate at the same frequency, but one support member 1151can be moving upward while an adjacent support member 1151 is movingdownward (i.e., adjacent support members 1151 may be operating 180°out-of-phase with respect to one another).

Even when a single vibrational element 1150 is employed, it can bedifficult to precisely control and coordinate the phase and frequency ofthe vibrational force transmitted to the wire by two or morevibration-inducing mechanisms 1104. In order to coordinate the phase andthe frequency of force generated by two or more of thevibration-inducing mechanisms 1104, the vibrational elements 1150 can berigidly supported to the support members 1151 (whether sharing a commonvibrational element 1150 or otherwise). For example, the vibrationalelements 1150 can be rigidly supported the sliding mechanisms 1148(described below) mounted to each support member 1151 in order toeffectively transmit the vibrational force through the support members1151 to the vibrational elements 1150. However, when one vibrationalelement 1150 is coupled to more than one vibration-inducing mechanism1104, several problems may occur. First, the support members 1151 mayvibrate out-of-phase until the speed of the vibration-inducingmechanisms 1104 cannot be adjusted by the feedback control system. Thiscan occur when vibrational frequency from one support member 1151 istransmitted to an adjacent support member 1151 to an extent that “noise”from a first vibration-inducing mechanism 1104 on the first supportmember 1151 cannot be filtered from the detected movement of theadjacent support member 1151 (e.g., measured by an accelerometer coupledto the second support member 1151). Second, out-of-phase support members1151 can cause the corresponding vibration-inducing mechanisms 1104 tolock and be unable to rotate or otherwise operate. Third, out-of-phasesupport members 1151 can produce extreme stresses on a sharedvibrational element 1150 at a transition point between adjacent supportmembers 1151. Extreme stresses can be imposed on the vibrational element1150 when the phase of one support member 1151 tries to impose itselfonto an adjacent support member 1151.

In some embodiments, phase control of two or more vibration-inducingmechanisms 1104 can be achieved mechanically by drivably connecting thevibration-inducing mechanisms 1104 together. By way of example only,some vibration-inducing mechanisms 1104 employ aneccentrically-positioned mass rotatable with an axle of thevibration-inducing mechanism 1104. The axles of two or morevibration-inducing mechanisms 1104 can be drivably connected in anyconventional manner (or a common axle can extend to and be shared by twoor more vibration-inducing mechanisms 1104) in order to simultaneouslydrive the eccentric masses of the mechanisms 1104 in phase. In otherembodiments however, no such common axle or coupled axles exist.

Another manner of support member phase control is illustrated by way ofexample in FIGS. 14 a-16. With reference first to FIGS. 14 a, 14 b and16, the vibrational head 1106 can include sliding mechanisms 1148 and avibrational element 1150 (e.g., a vibrational foil) coupled to thesliding mechanisms to mount the vibrational element 1150 to the supportmember 1151. The sliding mechanisms 1148 can be connected to thevibrational element 1150 in a number of different manners, such as byany of the sliding connections shown in FIGS. 7 a-7 c and 8 a-8 e. Asshown in FIGS. 14 a, 14 b and 16, the vibrational head 1106 includessliding mechanisms 1148 each having a T-shaped configuration. However,the sliding mechanisms 1148 can have any other configuration suitablefor slidably coupling the vibrational element 1150 to thevibration-inducing mechanisms 1104. Any other slidable and non-slidablemanner of connecting the vibrational element 1150 to thevibration-inducing mechanism (including without limitation any of thosedescribed above with reference to the embodiments illustrated in FIGS.1-13) can instead be employed as desired. Sliding mechanisms 1148 (ifemployed) allow the vibrational element 1150 to be removed from thevibrational device 1000, 2000 and to be replaced—in some embodimentswhile the papermaking machine is operating.

With continued reference to the illustrated exemplary embodiment ofFIGS. 14 a-16, the vibrational device 1000 can include a singlevibrational element 1150 mounted to more than one support member 1151.Any one or more of the support members 1151 can be coupled to one ormore different vibration-inducing mechanisms 1104. Also, any number ofvibrational elements 1150 can be mounted to two or more support members1151. For example, as shown in FIG. 15, four support members 1151 andfour vibration-inducing mechanisms 1104 are coupled to a singlevibrational element 1150. In this regard, the single vibrational element1150 can be coupled to more than one vibration-inducing mechanism 1104(whether independently controlled or not). In some embodiments, each oneof the vibration-inducing mechanisms 1104 is independently controlled,but each of the vibration-inducing mechanisms 1104 transfers avibrational force having the same frequency to a common vibrationalelement 1150.

In order to align the phases of the vibrational forces transferred bymultiple support members 1151 sharing a common vibrational element 1150as described above, one or more dampening mechanisms 1200 can bepositioned between, adjacent to, or in any suitable position withrespect to the vibrational element 1150 and/or the sliding mechanisms1148. The purpose of these dampening mechanisms 1200 (referred to hereinalso as “dampeners”) is not to eliminate vibration passing to thevibrational element 1150 (the vibrational element 1150 still vibrates ata desired frequency and amplitude), but instead to dampen suchvibration.

As shown in FIGS. 14 a, 14 b and 16 by way of example only, in someembodiments the bottom of the vibrational element 1150 includes one ormore recesses 1153 within which the dampening mechanisms 1200 can bepositioned (i.e., the dampening mechanisms 1200 can lie between thesliding mechanisms 1148 and the walls that form the recesses 1153 in thevibrational element 1150). In some embodiments, the dampening mechanisms1200 can include male portions 1202 (e.g., T-shaped or dovetail maleportions) that can be positioned within corresponding female portions1155 in the recesses 1153 of the vibrational element 1150.Alternatively, the dampening mechanisms 1200 can merely lie between thevibrational element 1150 and the sliding mechanisms 1148 and/or can besecured to one or both of the vibrational element 1150 and the slidingmechanisms 1148 in any suitable manner (e.g., bolts, screws, buckles,clips, mating pins and apertures, rivets, threaded connections, snap-fitconnections, press-fit connections, adhesives, resins such as epoxy orsilicone, cohesive bonding material, and the like). In this regard, thedampening mechanisms 1200 need not necessarily be recessed within thevibrational element 1150. However, in other embodiments the dampeningmechanisms 1200 are received at least partially within recesses in thevibrational element 1150 and/or the sliding mechanisms 1148. Ifrecessed, the dampening mechanisms 1200 can be retained within therecess(es) in any of the manners described above.

In some embodiments, a secondary support member 1157 is positionedbetween the vibrational element 1150 and the support member 1151. Thesecondary support member 1157 can take the form of an elongated elementto which the vibrational element 1150 is coupled, and can extend alongthe support members 1151. In some embodiments, the secondary supportmember 1157 extends at least partially across adjacent support members1151, while in other embodiments the secondary support member 1157extends only along a corresponding support member 1151 (in which caseeach support member 1151 can have a corresponding secondary supportmember 1157 employed to connect the vibrational element 1150 to thesupport member 1151).

As shown in FIGS. 14 a, 14 b and 16, the bottom surface of thevibrational element 1150 can include a male engagement surface 1159(e.g., a T-shaped male engagement surface) that can be permanently orremovably positioned within a corresponding female engagement surface1161 in the secondary support member 1157. However, any number ofreleasable or non-releasable fasteners can be used to couple thevibrational element 1150 to the secondary support member 1157, such asT-shaped mating surfaces, dovetail mating surfaces, bolts, screws,buckles, clips, mating pins and apertures, nails, rivets, threadedconnections, snap-fit connections, press-fit connections, and the like.Similarly, adhesives or resins (e.g., epoxy or silicone), cohesivebonding material, welds, and brazing can be used to couple thevibrational element 1150 to the secondary support member 1157. Thisconnection can be made employing any of the other manners of connectiondescribed above with reference to the direct connection between thevibrational element 1150 and the support member 1151. Moreover, variousembodiments can employ none, one, or some of the above-describedfasteners and methods of attachment. Alternatively, the vibrationalelement 1150 and the secondary support member 1157 can be comprised ofone integrally-connected member.

Dampening mechanisms 1200 can also be positioned between the slidingmechanisms 1148 and one or more portions of the secondary support member1157. The secondary support member 1157 can include one or more flanges1163. In some embodiments, the flanges 1163 include female portions 1165that can receive the male portions 1202 of the dampening mechanisms1200. In this manner, dampening mechanisms 1200 can, in someembodiments, lie between the flanges 1163 of the secondary supportmember 1157 and at least one portion of the bottom surfaces of theT-shaped sliding mechanisms 1148.

In some embodiments, each dampening mechanism 1200 is comprised of afluid-filled tube or other flexible or deformable conduit 1201 thatextends along the entire longitudinal length or at least part of thelongitudinal length of the vibrational element 1150 (i.e., the length ofthe cross-machine direction of the wire). As shown in FIG. 14 b, thedampening mechanisms 1200 can be filled with fluid until they reach anuncompressed position 1204 (indicated in phantom). When the dampeningmechanisms 1200 are positioned with respect to the vibrational element1150, the sliding mechanisms 1148, and the secondary support member1157, the dampening mechanisms 1200 reach a compressed position 1206 andremain in that position during the operation of the papermaking machine.The fluid-filled dampening mechanisms 1200 therefore provide a dampeningfunction for the vibrational element 1150.

In other embodiments, the dampening mechanism 1200 does not expand to anuncompressed position 124 as just described, but instead retains a shapethat is increasingly resistant to flattening, compression, or otherdeformation with increased fluid pressure in the dampening mechanisms1200. In still other embodiments, the dampening mechanism 1200 providesdifferent stiffness properties based upon different internal fluidpressures regardless of the other properties of the dampening mechanisms1200 at such pressures.

As described above, the dampening mechanism 1200 in the illustratedexemplary embodiment of FIGS. 14 a-16 includes at least one conduit 1201located between the vibrational element 1150 (or secondary supportmember 1157) and the support member 1151. It should be noted that thedampening mechanism 1200 can be defined by a single conduit 1201 passingbetween these elements in one or more lengths or runs of the conduit1201 in the vibrational device 1000. Therefore, the four cross-sectionsof the dampening mechanism 1200 illustrated in FIG. 14 a can be the sameconduit 1201 or can be cross-sections of two, three, or four differentconduits 1201 of the dampening mechanism 1200. Also, the fluidconduit(s) of the dampening mechanism 1200 can extend alongsubstantially the entire length or any fraction of the length of asupport member 1151 in the cross-machine direction, and can extend onlyalong a single support member 1151 or can cross to one or more adjacentsupport members 1151. In this regard, a separate dampening mechanism1200 can be provided for each support member 1151. Such an arrangementcan provide separate control over the dampening properties of eachsupport member 1151 in a vibrational device, and at least the ability toemploy dampening mechanisms 1200 having different properties fordifferent support members 1151. Alternatively, two or more supportmembers 1151 can share the same dampening mechanism 1200 (e.g., theconduit(s) 1201 of a single dampening mechanism 1200 in some embodimentscan extend along two or more support members 1151). Such an arrangementcan still provide separate control over the dampening properties ofgroups of support members 1151 in a vibrational device, and at least theability to employ dampening mechanisms 1200 having different propertiesfor different groups of support members 1151.

In some embodiments, the fluid conduit(s) 1201 of the dampeningmechanism 1200 can be filled with fluid under pressure. Fluid (such asair, a gas, a combination of gasses, or a liquid) can be supplied to thefluid conduit in any conventional manner, such as by a pump, acompressor, or a pressurized vessel coupled to the fluid conduits 1201,and the like. If desired, the pressure of fluid within the conduits 1201can be selected to provide the conduit 1201 with a desired firmness,thereby providing a desired dampening for the vibrational element 1150.Also, in some embodiments the pressure of fluid within the conduits 1201can be adjusted in any conventional manner, such as by operating a pumpor compressor coupled thereto, operating one or more pressure relief orbleed valves coupled thereto, and the like. In still other embodiments,the dampening mechanism 1200 includes conduits 1201 that are neitherpressurized nor connected to any device or element for this purpose.Instead, the conduits 1201 are comprised of material capable ofdampening vibrations transmitted to the vibrational element 1150, suchas rubber or plastic, urethane, nylon, neoprene, and the like.

Although the conduits 1201 of the exemplary dampening mechanism 1200 runalong the length of the support members 1151 (whether in elongated runsof the same conduit 1201 running back and forth along the supportmembers 1151 or otherwise), it should be noted that the conduits 1201can run in a number of other directions or combination of directions inthe dampening mechanism 1200 while still performing the same functionsand still being located in the same positions as described above. Anypath followed by the conduit(s) 1201 can be employed as desired, andfalls within the spirit and scope of the present invention. Also, thevibrational device 1000 according to the present invention can have anynumber of conduits 1201 passing along any number of runs in thedampening mechanism 1200.

As described above, the dampening mechanism 1200 in the exemplaryillustrated embodiment of FIGS. 14 a-16 is positioned between thesliding mechanism 1148 and the vibrational element 1150 and secondarysupport member 1157. In other embodiments, the dampening mechanism 1200can be located between only the sliding mechanism 1148 and thevibrational element 1150 or only between the sliding mechanism 1148 andthe secondary support member. In general, the dampening mechanism 1200is located between the vibrational element 1150 (or element mountedthereon) and the support member 1151 (or element mounted thereon).Accordingly, although the dampening mechanism 1200 could be locatedbetween the upper surface of the support member 1151 and an adjacentfacing surface of the vibrational element 1150 by way of example only,the dampening mechanism 1200 in the illustrated exemplary embodiment islocated as described above and illustrated in FIGS. 14 a, 14 b, and 16.In other embodiments, the vibrational device 1000 has no slidingmechanism 1148 and/or secondary support member 1157 (e.g., embodimentsin which the vibrational element 1150 is connected to the rest of thevibrational device 1000 in other manners). In such cases, the dampeningmechanism 1200 is not positioned adjacent a sliding mechanism 1148and/or a secondary support member 1157, and is instead positioned in anyother manner between the vibrational element 1150 and the support member1151 suitable to dampen vibrations to the vibrational element 1150.

The dampening mechanisms 1200 in the exemplary embodiment of FIGS. 14a-16 are positioned between facing horizontal surfaces of thevibrational element 1150 (or secondary support member 1157) and thesliding mechanism 1148. However, it will be appreciated that theresulting damping functions can be achieved by dampening mechanisms 1200positioned between other surfaces of the vibrational element 1150 orsecondary support member 1157 and the sliding mechanism 1148. Forexample, the dampening mechanisms 1200 can be positioned betweenvertical surfaces, diagonal surfaces (with reference to the view ofFIGS. 14 a and 14 b), irregular surfaces, or surfaces having any otherorientation. Dampening mechanisms 1200 can therefore be employed todampen vibrations exerted in a vertical direction, in a horizontaldirection, in a diagonal direction, or in any combination of directionsbased upon the position of the dampening mechanisms 1200 between thevibrational element 1150 (or element mounted thereon) and the slidingmechanism 1148.

As shown in FIGS. 14 a, 14 b and 16, the dampening mechanism 1200 in theillustrated exemplary embodiment generally serves to dampen vibrationbetween the sliding mechanism 1148 and the vibrational element 1150and/or secondary support member 1157. As described above, in someembodiments pressure within the conduit(s) 1201 of the dampeningmechanism 1200 can be adjusted. For example, the stiffness of theconduit(s) 1201 can be adjusted so that the stiffness is sufficient totransmit vibrational force through to the vibrational element 1150, yetflexible enough to substantially eliminate or at least reduce thedifferences in phase that can occur between adjacent support members1151 along the cross-machine direction of the wire. In some embodiments,the conduit(s) 1201 of the dampening mechanisms 1200 can be adjusteduntil the phase of the vibrational force exerted on a shared vibrationalelement 1150 is substantially equal along adjacent vibrational elements,and along the entire cross-machine direction of the wire, if desired.Also, in some embodiments the conduit(s) 1201 of the dampeningmechanisms 1200 can also be adjusted so that the vibrational force fromone vibration-inducing mechanism 1104 reinforces the vibrational forcefrom an adjacent vibration-inducing mechanism 1104 through a sharedvibrational element 1150, thereby reducing the power required to operatethe vibration-inducing mechanisms 1104.

Although conduits (pressurized or not, and having controllable pressureor not) are employed in the illustrated exemplary embodiment of FIGS. 14a-16, other dampening devices and elements can instead be employed toperform the same functions just described (i.e., to reduce orsubstantially eliminate phase differences between adjacent supportmembers 1151 while still permitting vibration to be transmitted to thevibrational elements 1150). For example, the dampening mechanisms 1200can comprise strips, bars, pads, or other elements of resilientdeformable or other dampening material (e.g., rubber, plastic, urethane,nylon, neoprene, and the like), liquid-filled conduits, electromagnetsor magnetic rails, viscoelastic material, constrained-layer dampeningstructures, and the like. The dampening mechanisms 1200 can extend alongany part or all of the cross-machine direction of the wire.

In some embodiments, the width of the vibrational element 1150 isincreased in order to increase the amplitude of vibration. As shown inFIG. 14 a for example, the width of the vibrational element 1150 canextend beyond the width of the support member 1151. During operation,movement of the vibrational element 1150 can be substantially vertical,or can be rotational (in the view of FIGS. 14 a and 14 b), whereby thevibrational element 1150 and the support members 1150 move in a round,elliptical, oval, or other rotund path as the support members 1151 andvibrational element 1150 moves vertically upward and downward. Suchmotion can be enabled at least in part by the vibration isolators (notvisible in FIGS. 14 a-16) to which the support members 1151 are coupled.By increasing the width of the vibrational element 1150, more energy(i.e., a vibrational force having a greater amplitude) can betransmitted to the wire in some embodiments.

The embodiments described above and illustrated in the figures arepresented by way of example only and are not intended as a limitationupon the concepts and principles of the present invention. As such, itwill be appreciated by one having ordinary skill in the art that variouschanges in the elements and their configuration and arrangement arepossible without departing from the spirit and scope of the presentinvention as set forth in the appended claims.

1. A method of forming a web, comprising: discharging stock flow from aheadbox onto a wire, the stock flow including water and fibers;transferring a vibrational force produced by at least onevibration-inducing mechanism to the wire via a vibrational head;dampening the vibrational force with at least one dampener coupledbetween the at least one vibration-inducing mechanism and thevibrational head; and draining at least some of the water from the stockflow to cause the fibers to form a web.
 2. The method of claim 1,further comprising adjusting a pressure in the at least one dampener. 3.The method of claim 1, further comprising adjusting the at least onedampener until a phase of vibrational force generated by the at leastone vibration-inducing mechanism is substantially constant in a crossmachine direction of the wire.
 4. The method of claim 1, furthercomprising adjusting the at least one dampener until a frequency of thevibrational force generated by the at least one vibration-inducingmechanism is substantially constant in a cross machine direction of thewire.
 5. The method of claim 1, further comprising controlling afrequency of vibrational force generated by the at least onevibration-inducing mechanism with a feedback control system, thefeedback control system receiving signals from the vibrational headrepresentative of at least one of frequency and amplitude of vibrationalhead movement.
 6. The method of claim 1, wherein the at least onevibration-inducing mechanism comprises first and secondvibration-inducing mechanisms generating respective vibrational forces.7. The method of claim 6, further comprising transferring the respectivevibrational forces to the wire at different cross-machine directionsalong the wire.
 8. The method of claim 7, further comprising dampeningthe respective vibrational forces with first and second dampeners,respectively.
 9. A method of producing vibration for processing a layerof material, the method comprising: generating a vibrational force;transferring the vibrational force to a support; dampening vibration ofthe support generated by the vibrational force to generate a dampenedvibration; transferring the dampened vibration of the support to a headcoupled to the support; and dampening vibration of the headindependently of dampening vibration of the support.
 10. The method ofclaim 9, wherein generating a vibrational force comprises generatingmultiple discrete vibrational forces collectively defining thevibrational force.
 11. The method of claim 9, further comprisingtransferring another vibration from a second support to the head. 12.The method of claim 9, further comprising controlling a degree by whichthe vibration of the head is dampened.
 13. The method of claim 12,wherein the degree by which vibration of the head is dampened is atleast partially controlled by detection of the dampened vibration. 14.The method of claim 12, wherein the degree by which vibration of thehead is dampened is controlled by changing a pressure within a dampener.15. A method of producing vibration for processing a layer of material,the method comprising: generating a first vibration; transferring thefirst vibration to a first support at a first location; generating asecond vibration; transferring the second vibration to a second supportsubstantially simultaneous with the first vibration and at a secondlocation disposed from the first vibration; transferring a thirdvibration at least partially defined by the first and second vibrationstoward a vibrational head; dampening the third vibration to generate afourth vibration; and vibrating a vibrational head with the fourthvibration.
 16. The method of claim 15, further comprising controlling atleast one of the first and second vibrations based at least in part upondetection of the third vibration.
 17. The method of claim 15, whereinthe head spans across the first and second supports.
 18. The method ofclaim 15, further comprising adjusting an amount of dampening of thethird vibration.
 19. The method of claim 15, wherein the first andsecond locations are spaced along a length of the vibrational head. 20.The method of claim 15, wherein the first vibration has at least one ofa frequency and an amplitude different from that of the secondvibration.